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Groombridge 1618 b
General Information

Ursa Major


Groombridge System


Groombridge 1618 a

Orbital Characteristics

0.478 au


0.502 au

Semi-Major Axis

0.490 au

Semi-Minor Axis

0.48986 au

Hill Sphere

128 Planetary Radii



Orbital Period
  • 153.461 Earth Days
  • 132.047 Sironan Days
  • 132 Days (Calendar Year)
  • 133 Days every 21st Year (Calendar Leap Year)
Synodic Month
  • 31.054 Earth Days
  • 26.721 Sironan Days

7.924° (from stellar equator)

Satellite of

Groombridge 1618



Physical Characteristics
Mean Radius

0.820 R⊕


0.510 M⊕

Mean Density

0.925 ρ⊕

Equatorial Surface Gravity


Solar Rotation Period
  • 27.892 Earth Hours
  • 27 Sironan Hours
Axial Tilt

153.3° (Retrograde Rotation)



Average Temperature

19.85 °C

Maximum Temperature

59.72 °C

Minimum Temperature

-88.712 °C




128,244,458 (2544)

Surface Pressure

0.95 atm

  • Nitrogen: 79.183%
  • Oxygen: 20.443%
  • Argon: 0.223%
  • Carbon Dioxide: 0.093%
  • Neon: 0.044%
  • Other Elements: 0.014%

Sirona, officially known as Groombridge 1618 b, is a small UNSC colony in the Groombridge System, the first and only planet in the system, with the object formally suspected to be a gas giant in orbit around Groombridge 1618 in the early 21st century proven to be nonexistent. It is notable for the large number of resources that have uses within the medicinal industry, leading to the planet's development as a industrial world focused on the production of drugs and other medical supplies, leading to it being a target during the Insurrection and proving quite useful during the Human-Covenant war. Additionally, while not visible from the surface, a large number of Forerunner structures sat buried in the crust of the planet.

Sirona was one of the few UNSC controlled planets to escape the war still under UNSC control, with the Covenant refraining from glassing the surface. While the reasons they didn't do so are largely unclear, the large resistance put up by the UNSC Air Force and Navy forces in the system played a part, as well as the Covenant realizing that they only needed to blockade the planet to restrict UNSC access to the medical supplies and facilities offered by Sirona and gain control of the Forerunner ruins, an action that required far fewer ships than glassing. With the other battles that were raged in the four years of the Siege of Sirona, many UNSC historians believe that the Covenant had believed this to be the best course of action and had deployed fleets that could have enabled the glassing of the planet to other engagements.

Due to being a target in the Insurrection, the Human-Covenant war, and several postwar conflicts, Sirona is one of the most war-scarred planets that has never left the control of the UNSC. The largest contributor to the war damages on the planet was the 4 year long Siege of Sirona, which started in 2544 and ended only due to the diversion of the Covenant forces still in orbit of the planet to the Battle of Meridian in 2548.


In Celtic mythology, Sirona was the goddess of healing, primarily worshiped in East Central Gaul and along the Danubian limes. Particularly, she was worshiped by the Treveri. Sirona's attributes were snakes and eggs. Groombridge 1618 b received the name Sirona due to a large number of Celtic descendants, specifically Gallic, within the original colonists as well as a large number of medicinal products produced by the planet.


The flag of Sirona.

Sirona's flag, depicted above, is another reference to the Celtic origins of the settlers, indicated by the Celtic triquetra in the center of the flag. However, it also, less obviously, alludes to the other aspects of Sirona's settlement. First, each corner of the knot represents one of the three groups that participated in the colonization of the world, the UEG, the settlers of Celtic ancestry, and the crew of the colony ship. The circle in the knot helps indicate the UEG, taking inspiration from the central globe of the UEG logo, though it also symbolizes the inter-connectivity between the three groups of the settlers.

The colors of the flag are drawn from Celtic traditions as well and relate to the planet and settlers as a whole. First, the green at the top of the flag represents healing and growth when viewed in regards to the planet and colony, as it was a medicinal and agricultural world. Additionally, in terms of the people themselves, it represented the prosperity that the colonists sought.

Next, the yellow-gold at the bottom of the flag, resting between orange and yellow in hue, represents the clean air of the planet, and the confidence of the settlers in their endeavor. Another symbolic meaning of this color was the power of thought, tying into the mental effort put into the colony.

The white between the two represents the potential between the other two colors, symbolizing a blend between healing and the power of thought. This bridge presents hope for the colonists to establish a new world for advancing research into the healing arts. Standing on its own, the white represents protection and purification, echoing the desires of the colonists on a strange world.

The final color, black, surrounding the trinity knot, represents the absorption and banishment of negativity, serving as a visual embodiment of the need for the three separate groups of settlers to work together positively in order for them to survive. Furthermore, the black served as a representation of outer space, symbolizing the challenge the settlers had overcome to arrive at their new home and the void that surrounded them. Overall, it served to remind them that, while they were cut off from others by space, this negativity must be banished if they were to survive, and, as such, they had each other to rely upon.


The Forerunners

The Forerunners maintained a strong presence on Sirona during the height of their ecumene, notably as a medical world, where the Lifeworkers researched advances in medicine and, eventually, where flood specimens were studied during the Forerunner-Flood war. As such, many of the structures were built underground to contain potential outbreaks more easily. As such, many ruins of Forerunner civilization are present under the surface of the planet, though these were not discovered until many years into the Human-Covent war in 2540.

With the activation of the Halo array in 97,445 BCE, the Forerunner presence on the planet and all Flood specimens were destroyed. Following the event, no sentient life was reseeded on the planet, leaving only plants and non-sentient animal life to populate the world for the next hundred thousand years.

Colonization and Early Years

Following its discovery in 2147, and the Interplanetary Wars in the 2160's, Groombridge 1618 b was among the potential list of planets to colonize. However, it was not until the colonization of Reach by the Odyssey in 2362, which sparked the first wave of human extra-solar expansion, that ships were sent to the Groombridge system. These ships, containing mostly colonists from within a Breton revival group within the Gallic regions of the UN, landed on Groombridge 1618 b in 2368.

As the atmosphere and landscape of Sirona were already compatible with human biology, no terraforming efforts were needed, allowing for the colony to develop even quicker than many of the other Inner Colonies, surpassing even colonies that had been established one or two years prior in industrial advancement, such as the nearby (through slipspace) colony Crystal.

Research of the plants, minerals, and other resources located on the planet led to the discovery of the many medical uses for the planet's resources, leading to a large medical industry developing on the colony. Within the first decade of Groombridge 1618 b's colonization, several hospitals, industrial centers, and medical research facilities had popped up, establishing the planet as a medicinal center of the Inner Colonies. This medical focus combined with the heritage of the colonists led to the name Sirona being adopted by the inhabitants. In order to complement the industrial aspects of the planet's economy, a system of orbital elevators was built shortly following the founding of the colony. Eventually consisting of twelve tethers (each with six shafts) the facility saw the completion of its first six tethers in 2374.

Increasing development of the planet carried on peacefully through the years between the colonization of Sirona and the Insurrection, leading to a few large cities. However, most of this development was in the form of large agricultural or mining facilities, enabling the colonists to harvest the required raw resources for the medical industry on the planet, or gleaming medical research facilities. Most of the population lived in suburban settings rather than the skyscrapers within the cities themselves. As such, the cities remained relatively small, with the research facilities in the center, surrounded by suburban living, which itself was surrounded by farms, mines, and industrial production buildings. This format was followed for the majority of the planet's cities, with the exceptions being the capital city, Grannus, and the largest city on the mainland, Maponos. For Grannus, the structures had to be more densely packed, as the island on which the city was located didn't present enough flat land area to be useful for the large suburban sprawl. Instead, government, military, and interstellar trade and travel structures all resided in a shared cluster of center-city structures, surrounded by urban living high-rises. Maponos, alternatively, was the center of the colony's medical industry, and thus the richest of the cities on the planet. While it held a similar population density to Grannus, it also sprawled over a much larger land area.

Another area of development that Sirona saw prior to the Insurrection was the installation of several astronomical facilities in the 2400s. Recognizing the potential of the planet's mountains for optical astronomy and large desert for radio astronomy, several astronomical collaborations were attracted to the world over the years. As a result of the colony's booming economy, the proposed observatories were often quite elaborate and expensive. While several of these proposals were accepted by the colonial government alone, many of the most well-known plans saw Sirona partnering with other colonies to establish "sister" observatories. These included the Pi Square Kilometers Array (PSKA) collaboration with Meredith, proposed in 2468 and completed in 2476, and the One Kilometer Radio Aperture (OKRA) collaboration with Grannus, proposed in 2469 and completed in 2473.


However, a little over a century after the foundation of the colony, resistance to UNSC control in the Outer Colonies came to a head, sparking the start of the conflict known as the Insurrection in 2494. The first impact that this conflict had on the colony was the construction of six additional orbital tethers in 2495 to increase Sirona's industrial output capacity. This decision was made due to the importance of medical supplies to the war effort and Sirona's established dominance in the healthcare and medical research and production industries.

While Sirona was an Inner Colony and, as such, didn't have any rebel cells originate on the planet itself, keeping itself safe for the first few years of the conflict, the various rebel factions, such as the United Rebel Front recognized the value of having the planet under its control. With this in mind, many rebel operatives from several different cells immigrated to the population in an attempt to divert resources away from the UNSC and to the Insurrectionists, gather information for any future attacks, and sow discontent among the populace. While the first and second of these goals were successful to some degree, the third goal generally ended in failure, with several insurrectionist agents being turned in by the civilians they tried to convince to join the rebel cause. This unwillingness of the Sironan citizens to rebel against the UEG was mainly due to the excellent treatment they had received from the UEG due to the importance of their world.

This pattern of subtle manipulation of the planet continued for many of the beginning years of the Insurrection, one such example being a cell of the Pacem Network disguising itself as a hacktivist group in late 2497, eventually shut down by police action when Elena Zaytseva set off a chain of events that brought the attention of the cops to the group's headquarters. However, later into the Insurrection, during the second decade of the 2500's, the Rebel's began to grow more organized and direct. Holding several warships of there own, such as the Iliad, the United Rebel Front scraped together a small fleet in an attempt to break through Sirona's defenses, which were not yet as strong as they were during the Human-Covenant War. Managing to gather three larger warships, along with about a dozen smaller craft, this fleet coordinated with the insurrectionist agents on the planet to attack the military headquarters on the surface of Sirona.

This attack on the surface created a distraction which the small fleet used to jump into the system and regroup following the scattering due to the slipspace jump. Once they regrouped on the edge of the system, the fleet moved to the planet, the three larger warships and some of the larger small vessels engaging the fleet in orbit, while the rest of the vessels made a break for the surface in order to land more troops to assist with the battle on the surface. This started the First Battle of Sirona, one of the few full-out attacks by Insurrectionists on a UNSC held colony during the Insurrection.

At this point in time, the UNSC had relatively few forces around Sirona, for two separate reasons. First, the UNSC as a whole was deployed more into the Outer Colonies to put down the Insurrection at the source. Additionally, with the Groombridge system being so close to Earth, it wasn't expected for it to be attacked. Therefore, then UNSC had only stationed a few light frigates in the system to defend it from pirates or petty criminals, not expected to fight a fully armed opposing fleet. As such, the three Insurrectionist vessels were able to quickly overcome the UNSC forces in orbit, aided by the element of surprise. During this quick engagement, one of the Insurrectionist controlled vessels took a UNSC MAC round. This vessel deorbited itself to avoid further damage and crashed into the planet with just thrusters to slow its descent. Despite attempts to use these thrusters to achieve a soft landing, it still left a large gash along the trajectory of impact and created a ship boneyard in the deserts of the Sironan mainland.

The UNSC forces on the ground, however, reacted to the Insurrectionists much better, quickly quelling the initial ground assault. However, with the primary goal of the distraction being achieved, the Insurrectionist loss during the first ground engagement wasn't as damaging as it could have been, as the two remaining Insurrectionist vessels landed even more troops in the farmland outside the Sironan capital. This started the second half of the ground battle, with the Insurrectionist forces attacking the Sironan military HQ at Grannus Military Base, just outside the capital city. This attack lasted for several hours, eventually drawing to a stalemate before a UNSC task force arrived in orbit, destroying another of the Insurrectionist's vessels, and forcing the other to flee. With the system cleared, the UNSC could land more ground forces and fight off the Insurrectionist ground forces, eventually forcing a surrender of the surviving rebels.

Following the conclusion of the First Battle of Sirona, the planet faced no more battles during the Insurrection. However, it returned to contributing to the war effort by providing medical supplies and training. Additionally, the inadequacies of the planet's orbital and ground defense network were revealed, resulting in the start of construction of Orbital Defense platforms around the planet, and the stationing of a permanent Marine Corpse brigade on the planet, stationed at Bodua base on the Sironan Mainland. Additionally, several new military bases were established across the planet's surface. These developments proved quite beneficial in the upcoming Human-Covenant war but didn't see any real use in conflict until that point in time.

Human-Covenant War

Like many of the Inner Colonies, the first years of the war saw Sirona free of any conflict. However, the war did indirectly touch the world by increasing the production of medical supplies for military use compared to civilian use, increasing the defense budget, tightening military control, and focusing more heavily on the completion of the orbital defenses. This increased focus on orbital defenses saw the fleet in orbit of the colony strengthened and the ten orbital weapons platforms completed, each on par with the ODPs around Reach. Another side effect of this shift was an increase in the population of the world with families of the officers from the new defense fleet, support staff from the various military branches, and contractors, engineers, and other technical workers all flooding into the system. It was during this rush of activity that the previously relatively small cities on the world swelled to the more sprawling sizes that personified the modern years of Sirona.

However, the peace on this planet was soon to end. In early-2544, Covenant vessels managed to place a tracker on one of the last UNSC vessels fleeing Alluvion. Following the series of random jumps, this vessel, along with several others, ended up in the Groombridge 1618 system, seeking the planet's medical resources to rest and recover following the long-fought battle. This lead to the Fleet of Righteous Vigilance being dispatched to the planet to capture the human medical stronghold, starting the Siege of Sirona.

Siege of Sirona

Main Article: Siege of Sirona

Initial Contact

When the Fleet of Righteous Vigilance, along with several other Covenant vessels, arrived in the system on July 25, 2544, they discovered the large Groombridge Defense Fleet, comprised of 65 vessels at the time, bolstered by 22 damaged vessels that had arrived in the system from previous battles, several orbital repair stations, and the orbital defense grid around Sirona. Additionally, the Luminary on the fleet's flagship detected a vast amount of Forerunner relics under the planet, which had just recently begun to be found by the Humans living on the world. This, combined with the relatively few number of vessels but relatively large number of ground forces available to the Covenant led to the decision by the Prophet of Conviction to besiege the planet, rather than attempt to wipe out the UNSC defenses around the system and glass it directly, which contributed to the extreme length of the siege, excessive ground combat, relative lack of evacuation, and overall brutality of the fight, as the Covenant forces on the ground, specifically the multitude of Zealots deployed, led to a burning dedication to break through the human ground defenses and gain control of the Forerunner artifacts, which worked in the Covenant's favor.

An entrance to the ruins on Sirona. Built just before the Siege of Sirona.

However, several factors also worked in favor of the humans. These included the extensive spaceborne defenses of the planet, holding the Covenant vessels to the edge of the system where they could only serve to deter reinforcements, rather than directly engage, the veteran marines and large number of naval, consisting of both spacefaring and "wet" vessels, air force, and army forces available, including several ace pilots from both the air force and navy who directly contributed to the death of a large portion of the Covenant landing forces by shooting down their dropships, and the medical facilities already set up on the planet, allowing for quick but effective treatment of battle injuries, with many of the human defenders even able to get full surgeries and cybernetic replacements during the course of the battle. Combined, the advantages the Covenant had and the advantages the Humans had worked to extend the battle, with neither side truly able to get an edge, but neither side able to gain reinforcements, with the world fenced out by the fleet surrounding the system blocking the UNSC from sending new forces, and the deployment of Covenant vessels to other, more pressing battles, cutting off reinforcements for the Fleet of Righteous Vigilance.

Siege of Sirona: Phase One

The initial fighting during the Siege was in space, as the Covenant forces surrounding the system deployed massive waves of landing craft and fighters to defend them. Approaching the planet, the advancing Covenant ships were met head-on by the orbital defenses, with Naval fighters and point defense turrets on the capital ships in the system, as well as the defense platforms that were in position to engage, tearing the vessels to shreds. However, the sheer number of landing craft, the straight shot towards the planet, not stopping to engage, and the skill and zealotry of the fighter pilots in regards to protecting the advancing dropships, led to a portion of the Covenant ships making it through the blockade and landing on the surface of the planet. While only about two-thirds of the dropships, and only about ten percent of the fighters, survived the wall of defensive fire that was thrown their way by the UNSC defense forces, the sheer number that had been deployed led to several thousand Covenant forces reaching the atmosphere.

At this point, the defense of Sirona fell onto the air force, with most of the Navy vessels focusing on preventing any secondary wave from breaking through the defenses undetected. While the air force pilots fought fiercely, the same factors came into play in this engagement as did in the space battle, with the Covenant dropships making a dive for the planets surface, rather than engaging, and the remaining fighters handling the dogfighting, keeping the UNSC air force fighters from doing any real damage. During this stage, only another ten percent of the Covenant fighters were lost and a handful of the dropships were lost, while the UNSC lost an entire garrison of air force vessels and the few assisting Navy fighters, leading to the Covenant breaking through this second line of defense and reaching the surface.

Following the breach in the Human defensive lines, the Covenant forces landed on Sirona, mostly in Epona on Capital Island, and the Sironan Mainland Nature Reserve on the mainland. The ground forces quickly established their garrisons in these locations, but were contained for the first part of the battle by the quick response of the Army and Marine Forces located on the planet, as well as ODST's dropped from orbit, starting the long, drawn out, and bloody conflict on the surface, with neither side gaining or losing much territory. However, the Covenant did manage to push into the Sironan Mainland Nature Reserve, slowly making their way to the Super-MAC fusion reactor compound in the center of the dense forest. Contrary to this, the UNSC quickly repulsed the Covenant forces in Epona, and the "wet" Navy forces combined with the Air Force prevented any Covenant from landing on the capital island for the rest of the siege.

Siege of Sirona: Phase Two

ODSTs deploying to the surface of Sirona.

The long, drawn out ground campaign continued for some time, with the Covenant ships and UNSC ships holding their positions for about a year, neither side wanting to advance on the other for fear of being wiped out, the UNSC by the superior Covenant firepower at the edge of the system, out of range of the SMAC's, and the Covenant by the SMAC's and consolidated firepower of the stationary UNSC fleet, which would have had time to prepare, in orbit. However, in May 2545, the Covenant ground forces managed to seize the Sironan Mainland Nature Reserve fully, quickly disabling the SMAC fusion reactors located in the forest. Following the removal of the SMAC's from the equation, along with several UNSC ships being disabled by boarding parties over the past year, while the Covenant fleet remained relatively intact, the Fleet of Righteous Vigilance moved in to engage the UNSC Fleet in orbit around the planet. Quickly overrunning the Sironan Defense Fleet, a few Covenant frigates descended into the atmosphere to provide support for the ground troops, while the remaining Covenant vessels remained in orbit to provide defense against any potential UNSC counterattack. It was during this devastation of the Groombridge Defense Fleet that Admiral Elizabeth Whitaker was killed, leading to the commander of the "wet" navy forces, Rear Admiral, Upper Half Ross Logan, taking control of the UNSC Navy forces on and around Sirona.

Second Ground Campaign

Burning City.jpg

Bodua City and the Sironan Mainland Nature Reserve, respectively, each burning.

Even once the Covenant fleet broke atmosphere, the UNSC defenders still proved extraordinarily resilient and, unwilling to resort to any form of glassing, mainly due to the lack of ships to carry out low altitude glassing and the risk of damaging Forerunner artifacts if it was done from orbit, the Prophet of Conviction ordered that the fleet begin to besiege the planet once more. Burning the city of Bodua and parts of the nature reserve (along the coast) with conventional plasma weapons, the Covenant withered the remaining UNSC forces in those areas. With the UNSC forces on the mainland falling back to the Maponos City Combined Military Installation, the Covenant launched a two-prong attack, both besieging Maponos City and moving to take the Forerunner ruins in the mountain range near the city. While the UNSC managed to barely hold onto the city, with the conflict dissolving into Urban warfare, the Covenant managed to push through the mountain entrance to the ruins and, by May 2546, two years into the conflict, they had pushed the fight for the Forerunner ruins completely underground, into the ruins themselves.

For the third year of the siege, the battle was waged in two major fronts, the Defense of Maponos City, and the Defense of the Sironan Ruins, as well as the heavy UNSC fortification against Covenant advances on the Capital Island. The UNSC forces on the mainland were completely severed from contact with the rest of the planet and from each other. The forces remaining in the city surviving on leftover supplies from the surrounding farms, and the various buildings around the city, specifically in the center, which was the most fortified. Contrary to this, those forces underground managed to connect to the mainland headquarters, located at the Maponos City Combined Military Installation, a few kilometers outside of the city and another stronghold of UNSC resistance. However, the supply lines between the underground ruins and the installation were often rather dangerous to traverse and patrolled by Covenant, so those underground fared about the same in terms of living conditions, compared to those fighting in the city, and, at times, had to resort to sharing weapons between marines due to lack of combat supplies and ammunition, with some UNSC marines resorting to utilizing discarded Covenant weaponry, despite the alien design.

The underground ruins on Sirona during the Siege

However, these two fronts fell down to one, the one in Maponos city, with the fall of the Maponos City Combined Military Installation during April 2547. With their supplies cut off and now completely surrounded, the remaining UNSC forces in the underground ruins quickly fell to Covenant forces, facing slaughter after slaughter until the last remaining forces were wiped out by June 2547. With this done, the Covenant dedicated a large portion of their forces to exploring and acquiring Forerunner technology from the ruins, with the other half of the forces that were in the ruins being redirected to Maponos City, doubling down on the last remaining UNSC forces on the mainland. It was at this time that, in an effort to better command the forces on the mainland, Brigadier General Suzanne Gaume was shot down en route to Maponos City. As such, command of the marine forces trapped on the planet fell to Colonel Helen Vasquez, who command the defense through the entirety of the Siege's final year.

Final Year

Brute attacking UNSC forces in Maponos City

With twice as many Covenant forces swarming the city, the UNSC presence in Maponos was even more hard pressed to survive, with conditions quickly deteriorating and UNSC numbers dwindling until only about an eighth of the original detachment. However, at this point, the ground forces had managed to fortify several buildings in the center of the city and casualties slowed for the UNSC and increased for the Covenant, who still refrained from directly bombarding the area, instead relying on siege tactics. While the food, military, and medical supplies from the buildings did hold out for a while, especially with the reduced numbers, eventually they began to run out, and many of the surviving soldiers fell ill, died of starvation and exhaustion, or simply lost the morale to continue fighting and broke down.

However, just when things seemed to be at their worst for the mainland forces, the UNSC garrison on Capital Island had managed to almost completely repel the Covenant and sent a group of Pelicans to resupply the forces in Maponos, who had briefly managed to get a message out due to the skills of their pilots and the recovery of a Police Pelican during a nighttime patrol past Covenant lines. Additionally, just a few months later, in March 2548, the Covenant fleet above the planet was called away to the Battle of Meridian, recovering some of the ground forces but leaving about a third behind to continue the fight. Resurging against the remaining Covenant troops, the UNSC Marines on Sirona managed to fully clear the planet by May 2548, and Naval reinforcements soon arrived.


Following the conclusion of the siege, Ross Logan was given a promotion to Vice Admiral and took official control of the newly reformed Groombridge Defense Fleet. Alongside this promotion, Colonel Vasquez was promoted to Brigadier General and also had her position as commander of the Sironan Marine Brigade made official. For the remainder of the war, the planet was left alone as, while the Covenant hadn't completely removed it from the picture, its tactical significance had drastically fallen, and many years of rebuilding were required to return it to even a shadow of its former productivity. As such, the Covenant focused on higher value targets until they were eventually defeated in 2552.

One such reason for the decrease in the significance of Sirona for the remainder of the year was the extreme loss of human life the battle had caused, both civilian and military. While there was relatively little plasma bombardment carried out during the siege, the Covenant forces in orbit had been ruthless in hunting down and destroying any ships attempting to flee the world, effectively shutting down any serious evacuation effort. This saw the recently surging population of Sirona near completely locked down on the surface of the world and, while pockets did put up a good fight, the sheer relentless brutality of the Covenant siege tactics and ground assault saw many of them perish, leaving the population of the world a shell of its former size. When paired with the fact that the Covenant knew the location of the world and could come back and attack at any time, pushing many of the survivors to leave the planet, very few individuals were left on Sirona to work on the rebuilding efforts while the war still lingered. It wasn't until the end of the war and the influx of former colonists, their families, and new individuals seeking to rejuvinate the world they once heard great stories of that any serious progress was made on restoring the planet to it's former levels of prominence.

Post-War Conflicts

It was now, following the war, that Sirona began recovering quickly, at least considering the vast damages it had received during the siege. However, despite the industrial recovery the planet saw, allowing it to return to its position of prime medical supply producer of the UNSC by 2555, much of the damages to the natural world lingered. As such, it is easy to see where major battles had happened on the planet, such as in the Forerunner ruins, which were heavily damaged, or the nature preserve, in which, among the new growth, large swaths of trees and shrubs remain charred and dead. While efforts to restore the nature preserve progressed smoothly, the damage was extensive and some areas remained visibly scarred even through the late 2550's. Additionally, attempts to restore the ruins were met with roadblocks by protest groups arguing that they should remain as the were, some as a sign to the people about the costs of war, others merely on the principle that the battle that had taken place inside them had just as much historical significance as the ruins themselves. As such, efforts progressed to the point of stabilizing the caverns containing the ruins to allow for further study but any further progression happened at a snail's pace, with the vast majority of the site in the same condition the battle had left it in by 2558.

Insurrection Reignited

Regardless of these setbacks, the recovery of its position within the UNSC once again made Sirona a prime target for insurrectionists during the postwar continuation of the insurrection. While it remained peaceful through 2555, 2556 saw the planet return once more to conflict, as many discontent members of the population finally gained support from the New Colonial Alliance, who saw the value of the restored world to their cause. This support led to the discontented civilians to move from protest groups to guerilla cells, fighting against the establishment, weakening the UNSC forces on the world. While these guerilla tactics were relatively ineffective, seeing how the UNSC forces on the world had returned to their pre-siege numbers, they did provide constant distraction and fear amongst the military and civilian populace, respectively.

For the next year and a half, these guerilla strikes and terrorist attacks continued, and the small cells located on the world grew larger and more well known. While this was mostly due to their ability to remain rooted on the planet despite their weakness compared to the Sironan Armed Forces, a few of the larger attacks during the final months of the unofficial conflict began to more heavily affect the UNSC strength. By mid-2557, the guerrilla cells on the planet organized into a single group and took a small industrial town in the center of the mainland continent. Fortifying this position, the rebel forces on the world officially declared themselves part of the New Colonial Alliance and started a more conventional war with the UNSC forces, though still largely focusing on defense and small tactical strikes.

This situation soon changed, however. In late October 2557, the NCA forces on the surface of the planet led a daring, two-pronged assault on the UNSC forces. Deploying all of their forces, abandoning their stronghold, the insurrectionists, now under the command of NCA officers, split into two fronts, one assaulting the Maponos City Combined Military Installation and the other assaulting a shipyard just outside of Bodua city. While both of these groups distracted the ground forces on the planet, several bombers that had been acquired by the forces on the planet flew in below the radar and carried out a bombing run on Grannus Military Base. Though these bombers were shot down after the first run, enough damage had been done to disorient the UNSC Army leadership on the planet. This distraction allowed for the ground assaults on the military base and shipyard to break through the Army forces stationed in defensive positions.

At the Maponos City Combined Military Installation, the attacking rebels managed to segment off a portion of the facility and hold it as a stronghold, providing a constant distraction and running interference to prevent the military leadership from reestablishing itself in the facility, now that the Grannus base was disabled. At the shipyard, however, the rebels pushed the assault. As they advanced deeper and deeper into the facility, breaking past the disoriented, already understaffed defensive forces, they made their way to a docked frigate. Boarding the vessel, the rebels, with the help of mechanics who they had planted as undercover agents within the shipyard, managed to clear it of UNSC crews and launch into orbit, firing a missile volley at Bodua Base, temporarily disabling the Marine forces on the planet as well.

Breaking atmosphere, the stolen frigate gunned its engines directly for several of the orbital defense platforms. Grabbing the attention of the naval forces in orbit, the frigate, still operating under UNSC tags, managed to get a MAC round and volley of missiles off before its nature was discovered by Vice Admiral Logan, who had been cut off from communication from the ground. Caught by surprise, Logan made the critical error of the engagement, deploying a vast majority of the fleet's vessels to engage the single frigate, assuming that more ships were present due to the explosion of two orbital defense platforms. However, the rebels had abandoned the frigate, deploying back to the surface of the planet in dropships and several of the SOEIV's. Landing back at their garrison with stolen UNSC weapons, vehicles, and technology, the rebels left the frigate to be destroyed by an overwhelming portion of the defense fleet. However, this proved to be more of a ruse as, with the ship disabled and no longer considered a threat, the UNSC forces failed to notice that the nuclear warheads on the frigate had been armed and the reactor was set to overload. As the Admiral recovered from the embarrassment of disabling an uncrewed frigate, the combined explosive power of the multiple detonations disabled many of the UNSC ships in orbit, disoriented the others, and took out a third orbital defense platform.

New Colonial Alliance's Arrival

This rather successful mission for the insurrectionists on the planet proved to be merely a preliminary operation to the main assault on the planet that was to come. As the battle with the frigate commenced in orbit of Sirona, four New Colonial Alliance vessels, who had been waiting on the edge of the system, advanced on the planet. Arriving just as the frigate detonated, the NCA ships, stolen frigates, opened fire on the orbital defense platforms that remained facing the oncoming assault. After they disabled these with relative ease due to the surprise nature of the assault, the frigates pushed through the remaining thirty-two UNSC vessels, using their disorientation to avoid return fire. Once past the orbital defenses, the frigates descended on the planet around the insurrectionist stronghold city, deploying even more troops and equipment, before launching again and fleeing the system.

With their numbers bolstered and the Sironan military leadership in shambles, the rebels on the planet began fortifying for a full out assault on several of the major cities, with Grannus set as the primary target. Rejoined by the rebels that had been attacking the Maponos City Combined Military Installation, the insurrectionist military on the planet reorganized itself quickly, aiming to take advantage of the treacherous situation they had placed the UNSC forces on the planet in with their ambushes, tactically critical surprise attacks, and distraction strikes. In under two days, the rebels were once again ready to launch an assault on the UNSC, who had recovered relatively little in that time.

However, alongside the arrival of the NCA supplies and troops, new leadership took over on the planet. Now under the direct command of an NCA general officer, the tactics employed by the rebels on the planet changed. Rather than deploying in large groups divided into multiple, skilled assault teams against one or two targets, the new commander broke the forces on the planet down into four land divisions with a fighter and bomber wing to provide support from the sky. Sending these divisions out to assault Maponos City and Bodua as well as each city's respective military base, this new commander made the crucial error of not separating the division, instead marching and driving them as a large cluster straight at the target, believing that he could overwhelm the worn down UNSC forces with sheer numbers. Additionally, by dedicating the fighters and bombers to other targets, namely the "wet" navy bases in the oceans of Sirona, he failed to provide adequate air support to the infantry and armored troops and, in the process, lost practically the entirety of his air assets to the unmanned drones launched by the "wet" navy aircraft carriers, as the "wet" navy was one of the few portions of the armed forces to have relatively stable command lines at this point.

As each of the four divisions approached their targets, they first encountered Sironan militia defenders, who, using the guerilla tactics loved by the rebels for the first few years of their existence on Sirona, whittled down the numbers of the insurrectionists and slowed their assault. This gave the "wet" navy enough time to defend itself against the NCA air forces and then proceed to provide air support to the UNSC troops defending each target. By the time the insurrectionists made it past the militia forces, they suddenly found themselves facing off against regrouped marines and army soldiers as well as strafing runs from the unmanned drones. In almost as little time as it took the rebel forces to run their initial strike against the UNSC forces, they suddenly found themselves pinned down in all four locations and overrun. With his assault a failure and the insurrectionist armed forces decimated, either killed or captured, the NCA general who had taken charge of the assault surrendered and ended the second attempted takeover of Sirona by insurrectionist forces. Before the year was out, the last remaining rebel forces on the planet were rooted out and Sirona was once again firmly under UNSC rule.


With both Lieutenant General Arthur Carro and Major General Phillip Cadiou killed during this assault, and the remaining members of the UNSC command structure, including Vice Admiral Logan, facing severe embarrassment for their failures which had allowed the small rebel forces on the planet to make such a large assault possible, the Sironan Armed Forces had their command structure almost completely reconfigured, with Logan entering a forced retirement. Though the military forces on the planet did, once again, end up recovering fairly quickly, the high ranking officers in the new organization structure had been pulled from other locations around the galaxy from a younger selection general officers. Among these were Lieutenant General Dexter Copeland, Major General Carol Warren, and Vice Admiral Jake Mason, replacements for Lieutenant General Carro, Major General Cadiou, and Vice Admiral Logan respectively. However, Brigadier General Vasquez remained in command of the marine forces on the planet.

The New Colonial Alliance also faced a smaller amount of embarrassment due to the failure of the general who had taken over upon the arrival of reinforcements, though this was quickly brushed under the radar and the immense success of the initial moments of the assault was pushed to the forefront instead. This was used as propaganda to help drive the NCA towards the more militant stance that it held by 2558. Additionally, the failure provided much needed insight into what methods worked for the NCA and which ones didn't, allowing the assault on Sirona to show the strength of guerrilla-style attacks rather than full out assaults, which contributed to the lack of any future conventional attacks by the NCA in the following year, with the group instead carrying out more distraction and ambush oriented combat. As such, Sirona was one of the few planets to face a conventional battle between UNSC and insurrectionist forces.

Following the conclusion of this conflict, the scale of the engagement and the causalities on both sides led to it being considered a worse version of the similar, pre-war insurrectionist strike on the planet. As such, many Sirona natives have begun referring to it as the Second Battle of Sirona (as the URF attack was known as the First Battle of Sirona), a name that has since spread off-world, seeing popular usage by individuals, civilian and military, when regarding the battle.

Created Conflict


Sirona Main Cities Map.png
A topographical map of Sirona's populated region.

Orbiting around a dimmer star than the sun, Sirona is much closer to the planet than Earth is, yet still feels to have approximately the same climate. In fact, it was so similar, that very little terraforming had to be done to the colony, and humans could even survive, if not thrive, on the planet before any was done. This shocking similarity doesn't just stop with the habitability of the planet, but also in its size, though less so, with a radius that is only approximately 1,000 km less than Earths, and about 2,000 km greater than Mars's. Its surface gravity is similarly less than Earth's, yet not much so, about three-quarters as strong.

The world of Sirona is very rich in both minerals and plant life that are used for medical supplies and drugs, as well as fertile soil for agriculture. Additionally, most of the land is joined in one large mass, bordered by a large ocean with a few small to medium sized islands within this sea. This landmass sees a wide variety of landscapes, from jungles along the equator to rolling hills and grasslands, dry savannas and deserts, and lush deciduous and evergreen forests among the more moderate latitudes, and skyward reaching mountains, frigid boreal forests, and frozen tundra wastelands along the more severe latitudes. These features are, however, also moderated by distance from the coast, with the imbalance between the ocean and landmass separation leading to drier climates further inland and moister climates along the coasts. As such, equatorial regions far enough inland could still see savannah or desert compositions rather than the rainforests typically associated with those latitudes.

In orbit, Sirona has a single natural satellite, named Mullo after another Breton healing deity. This cratered moon had a relatively large size in comparison to the planet (about 6% of the planet's mass, five times more than the 1.2% shown by Earth's moon) providing very large tidal forces on the planet's one large ocean.


Maponos City.jpg
Maponos, the dominant medical research center of Sirona


  • Capital Island - Largest island off of mainland
    • Coast
      • Grannus - Capital City, Seccond Largest city on the planet
        • Grannus Military Base - UNSC Army Headquarters on Sirona, Largest garrison for Army troops
      • Epona - Large farming community outside Grannus, Small city in its center, Dominant agricultural region
        • Epona Air Base - UNSC Air Force Headquarters on Sirona
  • Sironan Mainland - Largest landmass on the planet
    • Western Coast
      • Maponos City - Largest city on the planet, Dominant medical region
        • Maponos City Combined Military Installation - Combined garrison of UNSC Army and Air Force assets
        • Fallen of Sirona Memorial - Memorial for native Sironans who gave their lives defending their world during the Siege of Sirona
      • Bodua City - Large City on the Sironan Mainland
        • Bodua Base - Headquarters and garrison for the Sironan Marine Brigade, officially known as the 19th Expeditionary Brigade
        • Bodua Memorial Hospital - Hospital in Bodua City, utilized heavily by the military during Siege of Sirona
      • Esos City - Small City on Sironan Mainland
        • Esos City Marijuana Fields - Growing fields for marijuana companies headquartered in Esos City.
      • Sironan Mainland Nature Reserve - Nature reserve on the Sironan Mainland
        • Sironan Mainland Nature Reserve Compound X - Super-MAC ground-based reactors
      • Sironan Orbital Elevator Facility - Twelve, six-shaft orbital tethers and supporting complexes
    • Inland Desert
      • The Boneyard - Remnants of an Insurrectionist controlled warship that was shot down during the First Battle of Sirona
      • Pi Square Kilometer Array (PSKA), Sirona -
      • One Kilometer Radio Aperture (OKRA), Sirona -
  • Sironan Ocean - The large ocean on Sirona
    • Shallows
      • Sirona Naval Base Alpha - Headquarters and garrison for "wet" naval vessels
      • Sirona Naval Base Beta - Secondary garrison for "wet" naval vessels
    • Depths
      • Sironan Ocean Air Force Base - Ocean garrison for UNSC Air Force assets on Sirona


  • UNSC Medical Facility Sirona
  • Sirona Station Alpha
  • Sirona Station Beta
  • Sirona Orbital Tether Counterweight Station
  • Sirona Superior IJP Scanning/Relay Station
  • Sirona Inferior IJP Scanning/Relay Station
  • Orbital Defense Platforms
  • Orbital Repair Platforms


Sirona is heavily vegetated, more so than Earth, with large portions of the land masses of the planet being covered in forests and jungles. Several species of the many trees, shrubs, and flowers of the planet offer medicinal properties. Additionally, the vegetation on the planet is quite sturdy, due to the high amounts of winds on the planet, resulting from the larger amounts of unequal heating experienced on the planet due to the land masses and ocean being more distinctly separated, with only one large occurrence of each. Alongside the natural vegetation, many human-introduced species have been planted, both for industrial medicinal use and for recreational use, such as marijuana, of which many families grew in small family plots alongside the heavy industrial production of the plant in Esos, which produced processed marijuana for recreational use both on Sirona and on other worlds.

Sirona's fauna is plentiful, with most of the species living within the jungle, and relatively few living towards the more polar climates, much like on Earth. Additionally, many species of maritime animals also exist, populating the planet's large ocean. Additionally, several species of fauna from Earth are present on the world, including dogs, cats, farm animals, and several species of birds.

Many of the plant and animal species on Sirona were killed off to dangerously low numbers or even extinction due to both over-hunting, industrial habitat destruction, and a large amount of warfare that the planet saw, which heavily scarred the planet. However, over the years since the siege, extensive conservation efforts allowed for much of the wildlife to begin an upward trend and once again begin spreading over the world again. Additionally, the plant life was reseeded due to the extremely valuable medicinal characteristics of much of it and has started to show signs of regrowth, though the burned husks of dead trees and brush can still be seen in various locations.

Specific Flora

  • Bloodvines:

Large, semi-carnivorous plants native to the jungles of Sirona, bloodvines tend to feed almost exclusively on the corpses of the surrounding fauna. Growing in particularly muddy patches, they put off a smell that is found attractive to many of the animals surrounding their habitat (though often described as similar to the smell of slightly overripe fruit by humans), luring in their potential prey. While the healthy creatures are strong enough to escape their touch triggered "jaws," more sickly animals tend to get caught up between the grip of the plant's mouth and the muddy terrain. This allows the plant to benefit from both healthy and weaker members of the animal species as the healthy members would eat the seed pods and spread the seeds for the plants and the weaker animals would provide additional nutrients after dying through the digestive enzymes located in the large "jaws" of the plants. The semi-carnivorous designation arrises as they are capable of limited photosynthesis, though the dead animals tend to be the primary source of nutrients for the plants due to the lack of direct sunlight underneath the thick trees above.

While not typically dangerous to humans, they don't seem to be able to differentiate between their prey and will still attempt to latch on, often resulting in minor lacerations and acid burns to a healthy individual, typically along the limbs. However, there have been a few cases where an unlucky jungle explored has found themselves in a similar situation to the sickly prey of these plants and ended up dying due to being trapped in their grip, typically with some form of broken limb keeping them in place. Such individuals, as is the most common case with these plants, tend to die from illness or lack of water rather than the plant itself, as the dissolving enzymes and acids work over a timescale much longer than the typical length a human can go without proper sustenance.

On the flip-side, the protein-rich diet of the plants translates into the plants themselves, often leading to them being considered a good vegetarian source of protein for Sironans. As such, a significantly higher number of bloodvines have been consumed by humans than humans have been consumed by bloodvines. This does, however, required careful preparation to be sure that the digestive fluids don't remain in the cut being served so as to avoid burning the esophagus of the individual consuming the meal.

  • Sporemoss:

Not a specific species but a group of moss species found spread across much of Sirona's surface. Like many of the fungi species native to the world, the sporangium of sporemosses are extremely flammable while the spores contained within have evolved to be nearly impervious to flame in a similar manner to the seeds of the California Lilac. It is believed this developed due to the plants originating in volcanic regions in which the ability to assist in clearing the ground and returning nutrients to the soil while also possessing spores capable of surviving the high temperatures would prove beneficial to allowing the plant to regrow. As such, over time, the mosses and fungi originating from these regions naturally selected for high production of certain flammable oils within the sporangium and fire-retardant coatings for the spores themselves. Eventually, these spread across the planet and maintained many of their traits through the occasional forest fire and similar incident. As such, sporemoss and the similar fungi are often the first organisms found in recently burned areas.

One aspect of sporemosses and the similar fungi that is of particular note for the colonists is the increased chance of forest and brush fires in regions containing these species. While this originally proved quite detrimental to the colonization effort, over only a few generations the Sironans grew quite adept at preventing and dealing with wildfires, even getting to the point of being able to use the sporemosses and fungi to assist in pre-burning measures to control the spread of such wildfires. Additionally, these organisms are often harvested for uses such as firestarting and to extract the oils for their medicinal uses as well as an ingrediant in certain biofuels.

Specific Fauna

  • Jabbers:

Native to the semi-arid regions of Sirona's central mainland area (surrounding the central deserts of the world), jabbers have been described as large enough to consume a rat that itself is large enough to burrow a man-sized hole. Despite this comparison, these birds remain largely herbivorous, with mild insectivorous traits among some of the species. As such, their diet consists mostly of shrubs, grasses, seeds, fruits, and flowers, with the insectivorous species also eating bugs such as Sironan locusts. Additionally, like many toothless birds, they possess a gizzard in which they store pebbles and sand to help grind the food they consume.

The name "jabber" comes from the "jabbing" motion often associated with these birds. In actuality, the motion is more of a pulling motion in which the bird grabs onto the stalk of the plant it wishes to eat and repeatedly pulls on it to remove it from its tightly held roots, making it look like it's jabbing the ground. This action extends to a true "jabbing" motion for the insectivorous jabbers, which peck repeatedly at the ground to stir up the Sironan Locusts and catch them for digestion. The various species tend to have preceding names based on location or diet to distinguish between them, such as "savannah jabber," "basin jabber," or "locust jabber." However, these names aren't entirely accurate as the species overlap in many areas, extend beyond their named regions, and, for the latter, don't eat exclusively the locusts.

  • Sironan Locust:

While not truly related to the locusts of Earth, the similar external appearance and swarming habits lead to this small insect's name being shared with the grasshopper species. Despite the similarities, many major differences do exist, such as the arachnid-like eight-legged nature of the creatures, Additionally, the thorax and abdomen of the creatures contain one more and one fewer segments than on an Earth locust respective, with the thorax having four fused segments, and the abdomen having ten individual segments, with only the first one being fused to the thorax. Additionally, they tend to eat other smaller insects rather than the mostly plant-based diet of Earth locusts.

Government and Society

Sirona was one of the most important worlds for the development of medical supplies and training for medical professionals throughout the UNSC. Several of the most prestigious medical schools were located on this world, as well as buildings for several medical companies, such as Optican. Large amounts of the agriculture and mining on the world focused on growing and harvesting and extracting the required plants, chemicals, and raw materials for the creation of the medical supplies and equipment produced on the planet. As such, it relied heavily on other colonies for their food products and other necessities. Most cities on the planet's, excluding the capital city, Grannus, which had housing for the government officials that worked in the city, had relatively few residential centers, as the urban community was reserved for medical schools, corporate buildings, research centers, hospitals, and other similar structures relating to the economy of Sirona.

Grannus, the capital city of Sirona

Most of Sirona's original settlers originated from areas with heavy Celtic influence. As such, the colony has a large Celtic influence itself, even present in its common name, Sirona. As such, the most popular languages, besides English, were all Celtic languages. Even when other colonists settled on the planet, the Celtic influences remained strong, and are still noticeable on the colony.

Sirona had is own government, located in Grannus. However, it was overseen by the CAA and later the UNSC and UEG following the absorption of the CAA. Sirona in its entirety never joined the insurrection as many other colony worlds did. However, following the war, several discontent groups within the populace grew into guerilla insurrectionist cells. Additionally, it was subject to a few attacks from groups such as the United Rebel Front due to the medical supplies present on the planet.


Sirona has an extensive network of public transportation systems. The most popular and well developed of these systems is the extensive network of maglev trains, including rails connecting each of the cities on the mainland, a rail connecting the mainland to Grannus on the capital island, and smaller rail systems within each of the major cities themselves. Additionally, the major cities have extensive, well-maintained road systems for both cars and ground-based public transportation internally, and at least one major road heading out of the city to connect to the highway system between cities, the bridge-tunnel between the mainland and the capital island, and the smaller country roads for the farming communities, though these rarely see use by any public transportation, instead mostly providing routes for farm trucks and other vehicles to get about the rural areas of the world. Finally, each major city has at least one spaceport and anywhere from a half dozen to about a hundred airports of different sizes for transport off-world and shuttles between locations. Finally, each major farming region has one to five airports to allow goods and people to have quick transport from the cities to the more rural areas of Sirona, though Epona is the only rural farming community with a spaceport, located in Epona city in the center.

Orbital transport is handled through two main systems. The first of these is the spaceports in each of the major cities, typically used for passenger and military travel in which price premiums and advanced technologies can make up for the lost efficiency in launching from orbit. For large cargo transports from orbit-to-surface or surface-to-orbit, Sirona maintains a large orbital elevator complex to the south of Esos. Composed of twelve orbital tethers—each containing six individual shafts—this facility links to a large orbital cargo platform to which cargo vessels can dock without having to enter deep into Sirona's gravity well. In addition, this complex houses warehouses, truck stops, maglev stations, and an airport for storage and distribution of the goods, with several of the planet's primary distributors maintaining a presence. This allows Sirona's industry to remain stable, providing a stable influx of non-local goods and a stable export of finished products produced on the planet for distribution to the rest of the colonies. As the sole point of entry for large-scale commercial interactions between Sirona and the rest of inhabited space, the orbital elevator is one of the busiest places on the planet outside of the cities themselves.


Main Article: Sironan Neopaganism

While Sirona had no official religion, and many small groups of various practices were present on the world, by far the largest was a sect of Celtic Neopaganism developed about twenty years after the original colonists arrived known as Sironan Neopaganism. A revival of Celtic Paganism in modern times, the pantheon was reorganized to feature Sirona as the primary goddess, inspired by the planet's name. One of the major aspects of the religion was the belief that the world of Sirona actually embodied the idea of the goddess herself, with the various lesser gods and goddesses making up the various aspects of the world. As such, the pantheon itself is seen as one goddess, Sirona, who is composed by the various other gods and goddesses to create the whole.

Following the Siege of Sirona and the scattering or death of many of the world's original inhabitants, the primary branch of the religion changed from that of organized gatherings and the original beliefs to a more nomadic religion, with individual practice and a focus on the individual doing what he or she could to one day restore the world of Sirona and 'heal' the 'broken goddess'. This new branch became vastly more popular galaxy wide as its followers were more spread out and sharing their beliefs on other colonies rather than simply centralized on the homeworld. By 2558, 87% of those practicing Sironan Neopaganism were of the branch formed during the Siege, while 8% were followers of the orthodox branch, mostly those who had returned to the world to rebuild following the war, and the remaining 5% were followers of various other minority branches.


Main Article: Sironan (Language)

The Sironan language is a Creole, largely of French and Breton, though also including a few influences from English, developed during the early years of the colony. While the majority of the original colonists partook the effort from a desire to have a new world to reestablish the Breton language, they found difficulty in doing so while also being able to converse with the mostly French-speaking crew of their colony ship. As a result, over the years, Sironan developed through efforts to cross-communicate, with the grammar (including some more grammatical vocabulary, such as pronouns and prepositions) largely deriving from Breton and the vocabulary, contrastingly, largely developing from French.


Though Earth was the UNSC's cultural, political, and commercial center of the UNSC, and Reach was the military center, Sirona was the medical center of the human colonies. As such, it was still afforded an extensive defensive grid. Though not as advanced or possessing as many large vessels as Reach's or Earth's, it still held a large fleet of frigates and destroyers.

The Groombridge Defense Fleet was made up of anywhere from 50 to 60 warships permanently. Additionally, there were 10 semi-mobile orbital "Super-MAC" defense platforms. Finally, 5 refit platforms were held in orbit above the planet. On the surface, a large detachment of UNSC Marines was permanently stationed to supplement the Army and Air Force forces present on the planet. It held one of the largest complements of Air Force personnel and assets out of all of Humanity's colonies.

  • Total Land Personnel: 97,381 [15,517 Marine, 61,800 Army, 20,064 Militia/Paramilitary]
  • Total Naval Personnel: 170,662 [19,700 Sailors, 16,604 Embarked Marines/ODSTs, 116,158 Ground Personnel, 13,200 "Wet" Navy Sailors, 5,000 "Wet" Navy Ground Personnel]
  • Total Naval Assets: 65 Space-faring Vessels, 100 "Wet" Navy Vessels [4 "Wet" Navy Carriers, 6 "Wet" Navy Aviation Cruisers]
  • Total Air Force Personnel: 42,850 [42,100 Airmen, 750 Embarked Marines (ODPs)]
  • Total Air Vehicle Assets: 3,386 [1,900 Air Force, 500 Civil Air Patrol, 500 "Wet" Navy, 486 Navy], 5 Orbital Defense Platforms
  • Serviceable Airports: 823
  • Defense Budget: cR. 27,224,000,000

(all numbers as of 2544)


Main Article: Sironan Militia

In addition to the official UNSC military forces posted on and around Sirona, the colony was also deemed large and important enough to maintain an extensive civilian militia force, fielding more personnel than the ground-based Marine detachment and about a third as many as the planet's Army corps. While officially a paramilitary force, the militia held a close relationship with the actual UNSC military branches on the planet, affording it valuable equipment, weapons, and cross-training. As a result, the Sironan militiamen were able to overcome many of the downsides that other colonial militias faced, maintaining good relations with UNSC military personnel and keeping up to a similar standard of effectiveness, though still limited by the part-time, volunteer nature of the group. Furthermore, the Sironan militia also fielded equipment, weapons, and vehicles unique to the civilian fighting force, with budgetary restraints forcing the group to contract from smaller defense companies that typical for the official military, with administrators believing this to be a more effective strategy than relying on older models, such as other forces did by fielding MA2s and M4s, for example.

Notable Sironan Natives


List of Appearances

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