The Swarm

The Swarm, also known as The Hive and The Wraith, was a vicious extragalactic species that invaded the galaxy in 2733. A race made up of various insectoid forms, The Swarm entered the galaxy with the sole purpose of consuming all sentient life within it. The subsequent Swarm War cost the lives of over 300 trillion Humans, Sangheili and Therans and destroyed or devastated over 20 million worlds of the Unified Coalition of Governments. Decades and even centuries after the end of the war, more questions remain unresolved than answered about the Swarm's origins and existence.

History
The Swarm are speculated to have invaded the galaxy once before, long after the time of the Forerunners. Based on unsubstantiated evidence provided by an unidentified source on Thera, which may or may not be a Forerunner AI, the Swarm invaded the world of Thera. According to the source, it defended the world, along with the Therans, who were technically descended from Forerunners, with 'fire and vengeance'. It is not known if this event was related to the Ancient War, an apocalyptic event before the de facto founding of The Allegiance. The only evidence for it was carvings in ancient temples and archaic writings in obscure, long-dead languages.

The first confirmed contact with The Swarm was in 2614, when they invaded and massacred the small Allegiance scientific research outpost of Radiance. Due to the infrequent nature of communications between the outpost and the rest of the Allegiance, its destruction was not known until 9 months later. After this event they vanished off the galactic radar for more than a hundred years, before reappearing in 2733, triggering the galaxy's most massive, bloody and costly war since the Forerunner-Flood conflict.

Physiology
Although it was first thought that the Swarm was a collective of multiple species, later evidence showed that the Swarm was of a shared genus with several subspecies or variations from what was otherwise a shared genetic code. This was supported by the fact that each of the Swarm types shared integral characteristics such as a tough exoskeleton and major internal systems, and shared large quantities of DNA with only a few major variations. It was theorised that these variations were not natural in origin but influenced and enacted by some unknown higher being/beings, though this remained totally unfounded.

The Swarm differ greatly between types, in size and many other areas. However, they all shared the same exoskeleton, formed of naturally occurring carbon nanofibre. They all maintained a core body temperature of 26°C, and shared their internal structure with little changes other than size.

Reproduction
The Swarm was not composed of organisms of one gender, rather each individual was hermaphroditic, sharing internal characteristics similar to what would traditionally be called male and female. Rather than reproducing asexually, which prevents ongoing genetic variation, The Swarm rely on organic hosts in order to reproduce. Reproduction was accomplished only by Tier 3 types, as this was the only tier to possess reproductive organs. Organic hosts would be incapacitated by a toxin produced by tier 1 Swarm (Clackers), then brought to a birthing chamber. Here, two Tier 3 Swarm individuals would inject into the live victim a substance, the composure of which is still unknown. This substance contained genetic material, which enabled the mixing of genes by unknown mechanics inside the host. Not only this, the offspring would begin to form inside the host's body, draining it of energy and mas and using this to grow. In the final stages, the offspring would hatch from their internal egg-like sacs, and literally consume the host from the inside out. As many as twenty newborn Clackers could emerge from a host in this way, which would then go on to incapacitate other living organisms for use as hosts, and eventually transformation into other Swarm types. Dead hosts could also be utilised as vessels for reproduction and offspring growth, though the Swarm was known to prefer living hosts over dead ones. The reasons for this are completely unknown.

Life Cycle
Individuals of the Swarm were born as Clackers from living or dead hosts, which would live in this form for an average of six months. During this time they would assist in further Swarm reproduction by incapacitating living sentient organisms for use as hosts. After their lifespan in this form, known as Tier 1, Clackers would transform into either Drones, Reapers or Harpies. This occurred in a 3:2:2 ratio, though how this was achieved is unknown.

These Tier 2 forms would live for between 15 and 25 years in this intermediate semi-adult form, often described as 'pseudo-adulthood'. Tier 2 forms lacked the biological toxin used by the Clacker to incapacitate hosts, while also lacking the reproductive ability of Tier 3 forms. Evolutionary, the function of this second life stage seems unclear in comparison to the clear functions of the Tiers 1 and 3, though it was speculated that most of the combat needed for host gathering, and therefore continued survival, is dependent on the Tier 2 forms, validating their usefulness and continued existence rather than fading away through natural selection.

Tier 2 forms would subsequently become Tier 3, with each Tier 2 form having a corresponding Tier 3 one. Tier 3 was composed of the largest Swarm forms and the only ones with reproductive capability. These would, in pairs, inject a proboscis into a living but incapacitated host, where their genetic material would mix. The resulting offspring would emerge about three months later as fully formed, albeit small, Clackers, starting the reproduction process again.

Transformation
The basic function of the Swarm Hive as a conglomerate relies on the ability of individuals to undergo a series of extensive physical changes, in order to advance to the next stage of development. The Swarm uses extremely complex technology to accomplish this, taking the form of hollow half-organic, half technological chambers, varying in size to accommodate multiple types. Once inside these chambers, the being is suspended in liquid of unknown properties in an unconscious state. The being is kept alive by numerous life support systems, while biological processes initiate a change in the individual's physiology. Once the cycle is complete, the liquid drains from the sealed chamber and the being reawakens, entirely different. The transformation cycle can take as little as six months from a Tier 1 to a Tier 2 form, or as long as 12 months for change from a Tier 2 to a Tier 3 being. Ground-based hives had large sections devoted to transformation chambers, while starships generally had smaller, though similar, incarnations of this.

Behaviour
Although specific Swarm behaviour varied between forms, The Swarm was unilaterally hostile in its behaviour towards any living beings other than themselves. Vicious, violent and brutal, less intelligent Swarm types were incredibly violent instinctively. More intelligent forms such as Drones and Tier 3 types were deliberately destructive and tormenting towards their enemies, leading to the line of thought that The Swarm was an inherently evil and cruel species. It was widely documented that more intelligent types intentionally caused as much pain and suffering as they could, going out of their way to inflict as much physical and mental pain to their victims as possible. For the Swarm, sadistic and torturous behaviour was just a normal part of their existence.

Swarm individuals were extremely hive-oriented, and all forms felt a certain degree of discomfort when outside the cramped, damp and labyrinthine confines of either hives or Swarm vessels. The Harpy, for example, kept in swarms of around 40 as a result of this discomfort. Swarm were naturally at home on board any form of vessel and could very easily overpower enemy warships, where the close confines of a ship were a natural setting for the hive-oriented Swarm, and perfect for savage melees and brutal ambushes.

Swarm Types
Despite the fact that The Swarm was one single species, there were several different 'forms'. The lowest and most basic form of Swarm was the Clacker, which was theoretically the true larval form of the Swarm. These entered their second life stage as Reapers, Drones or Harpies, in a sort of pseudo-adult intermediary stage. Following this was the last, fully formed adult stage, Harpies becoming Dragons, Drones becoming Trolls and Reapers becoming Tarantulas. It is unknown is the Constrictor shares in this three-tiered system, or how they would fit into it if they did.

Among those studying the Swarm's anatomy and physiology in an attempt to combat them, the Swarm was essentially split into three tiers. The bottom tier, or Tier 1, was composed entirely of the larval Clacker. Tier 2 was formed of Harpies, Reapers and Drones, while Tier 3 comprised of Trolls, Dragons and Tarantulas. Constrictors were usually exempt from the strict tier system as they did not properly conform to the three tiered hierarchy.

In addition to the distinct subspecies making up The Swarm, most of the forms featured several subtypes that were distinguished not by anatomical differences but by functional usage.

Clacker
The lowest, most basic and most common form of the Swarm, Clackers were the larval form of Harpies, Reapers and Drones, which they transformed into after about 2 years of life. Effectively the first and original larval form, this type spawned all those above it and, although not often used in combat, were effective as rapid melee units complementing the larger Reaper. The mechanism by which an individual Clacker's adult form was determined remains a mystery. Clackers were small and agile insect-like creatures, averaging a metre in length and acting in a ground support role for other infantry. With vicious claws and dreadful bite, Clackers were so named for the chomping noise of their pincers and the horrible crunch made when they engaged their enemies. Unintelligent by Swarm standards, Clackers were incapable of sentient thought or anything beyond animal instincts and urges. Clackers were vital to the Swarm's continued existence as they incapacitated potential hosts for later reproduction, using a potent biological toxin produced in the Clacker's large jaw. This toxin was enough to incapacitate an Elite twice over for several days; usually the host would not regain consciousness until it was far too late.

Tier 2
Tier 2 Swarm types were essential for Swarm reproduction in that they were highly adapted to combat against organic enemies, which enabled Clackers to later retrieve both living and dead individuals for use as hosts. Tier 2 forms were very widespread and effectively the first line of the Swarm. The Tier 2 stage, unlike the larval Tier 1 Clacker or the full adult Tier 3, was essentially a middle ground between the two, a sort of pseudo-adulthood phase.

Drone
Drones were the most simple and most numerous of the Swarm forms following the Clacker. They were more intelligent than the other forms, possessing knowledge and learning skills just like a human or Theran would. Their average height was around 2m, though they could grow as large as 250cm before the end of their lifespans. They were stronger than the average human and possessed extraordinary endurance and resilience. Their faces were insectoid and their shape human-like. They possessed enough dexterity to wield most weapons in battle and could hold their own during combat situations. They were born already 6 feet tall and ready to fight, and continued to grow until the end of their lifespans which generally lasted about 20 years. They possessed tough exoskeletons which acted as natural armour to a certain degree, though it generally protected less from blades and as a result bladed weapons were popular throughout the war. Drones had to shed their exoskeletons every three to four years as they outgrew them. In actual fact, Drones were the adult form of Clackers, from which they transformed into after about two years. The older a Drone was, the more powerful it was and the higher it ranked in terms of military, with the oldest commanding vehicle formations or large numbers of infantry, similar to field commanders. Following their time in this form, Drones would transform into Trolls, ending their pseudo-adult form and entering their final adult stage.

Reaper
Reapers were quadrupedal wolf-like organisms which the Swarm utilised in a rapid attack and melee role akin to shock troops. They were extremely fast, resilient and terror-inflicting, quickly decimating large numbers of infantry. They stood at an average of 190cm tall and were 260cm in length, and featured large razor sharp spines on their backs, and jaws that could crush a soldier's battle armour. They could commonly be seen charging directly at infantry or light vehicles at ferocious speeds, a powerful psychological weapon against enemies. They were sometimes used as stealth units, as their speed and hunter-like skills, not to mention their silence, meant they could easily infiltrate enemy territory and wreak havoc. While their use against infantry was famed and successful, they were rarely effective against armoured vehicles. Reapers were the Tier 2 form of Clacker; after a lifespan of roughly 25 years, Reapers would become Tarantulas after an extensive transformation process.

Harpy
Often used as basic fodder units alongside the Drone, Harpies were much stronger and more potent however they were not nearly as intelligent. They were used akin to air support, also as rapid melee units to quickly engage enemy forces. They could easily pick up a fully armoured soldier and carry them to their deaths or feast on them on the wing. In large swarms they even posed threat to armoured vehicles and serious danger to less maneuverable air support vehicles, a notable example being the AV-14 Hornet. Armed with extremely powerful wings and razor-sharp blade-like legs, the sight of Harpies on the horizon often heralded the end for ill-equipped infantry. They were, however, quite weak against anti-air batteries, SAMs and more rapid air vehicles. Harpies were the larval form of Dragons, however not all of them transformed into them, with about 20% staying as Harpies and growing to large sizes.

Tier 3
The third Tier of the Swarm is made up of the oldest, largest and most mature of the Swarm types. These individuals went through stages 1 and 2 unharmed to reach the top level in Hive society. It fell to this tier to reproduce, whereby two individuals of any type would combine genetic material through an organic, non-Swarm host. Rarer than Tiers 1 and 2 in combat, Tier 3 forms were nonetheless the most powerful and feared of all the Swarm types, often being large enough to defeat armoured vehicles with melee force alone. Tier 3 forms had incredibly long lifespans and continued to grow in size and strength for the entirety of their lifespans.

Troll
The Tier 3 form of the Drone, Trolls were strange insect-like creatures with six pincer-like legs, a long, serrated pointed tail, and two large mandibles. Somewhat similar in appearance and size to the Dragon, Trolls, like Dragons and Tarantulas, had inordinately long lifespans and continued growing until their death. Upon hatching Trolls were typically about two metres in length, with the largest sighted being well over 30m in length. Trolls were less used on the battlefield as Dragons, which typically filled the same role akin to light or medium vehicles, depending on their size, with various weapons mounted onto their exoskeletons. Trolls were known, however, to be brutally violent in melee combat, more so than Dragons; incidents have been documented of lone Trolls decimating entire infantry squads near-effortlessly. Trolls were typically more involved in reproduction than Dragons which were used more as frontline combat units.

Dragon
Dragons were the Tier 3, adult form of the Harpy. After roughly 15 years of life, Harpies would spend six months in transformation chambers becoming Dragons. After this time they would emerge as fully formed, though small, Dragons, and being rapid gains in size. Dragons have roughly horizontal main bodies, from which four legs spread, and which terminates in a large raised tail, like a scorpion's, only serrated. At the front, its body rose more vertically off the ground, where in place of arms, two huge pincers sat instead. Its head was dominated by a large, mandible-flanked mouth, set with two small completely black eyes. Smaller Dragons were used akin to light vehicles, infantry support and weapons platforms, while larger ones took on more demanding roles and were equipped with more weapons. Dragons, like all Tier 3 forms, continued growing in size until their deaths, at the end of very long natural lifespans. Dragon's exoskeletons were thick even by Tier 3 standards and concentrated heavy anti-vehicle fire or orbital strikes were the optimum choices for engagement.

Tarantula
Tarantulas were the fully adult form of the Reaper. When emerging from their hatching chamber they were generally about two metres in length, but upon hatching they undergo a rapid growth period, quadrupling their size in under six months. Tarantulas had lifespans measured in centuries, and did not stop growing all their lives. The largest seen ones were over fifty metres across, though it was speculated that larger ones inhabited Swarm colony worlds. Tarantulas were used on the battlefields in a manner similar to Covenant Scarabs, ultra-heavy assault platforms for engaging all types of enemy units and instilling fear into the enemy. Possessing enough natural exoskeleton armour to withstand brief periods of concentrated Particle Cannon fire, Tarantulas of larger scales were more than a match for most opposing ground armour, though they suffered from poor speed. Larger Tarantulas were mounted with modular weaponry mounts, allowing for a specific Tarantula to be configured for a specific battlefield role.

Queen
Queens were a type of Tarantula used for a very different purpose. While still technically a Tarantula, and being physically no different, Queens were so named for their roles and behaviour. Queens were the controllers of starships, being mentally connected to a vessel's organic consciousness. The Queens controlled the vessels and interacted with each other, carrying out orders from above and issuing their own to their subordinates. The largest Queens could be found controlling Hive Ships, with some reaching over 200m in diameter. Queens never left their vessel, and were constantly connected to the ship mentally, the two sharing a symbiotic relationship; without one, the other would die. A vessel's Queen was also tasked with producing offspring, doing so alongside lesser Tier 3 forms and producing a larger number in comparison to others. Queens could live for thousands of years as their vessel supported their physical form, and also accommodated its physical growth (although in later years a Queen's growth would slow considerably). If a Queen was killed or seriously injured, it was likely that the vessel would die also, though it is unknown how this occurred. Similarly if a vessel was heavily damaged, the Queen would feel the ship's 'pain' and suffer also.

A Queen was speculated to have commanded members of her Hive or vessel through some form of mental communication, which also allowed a Queen to be passed on information from members of its Hive. Queens of Hive Ships were generally in overall control of a fleet and gave orders to the Queens of lesser vessels. It can be presumed that the strength of a Queen's mental communication ability grows with age and increases in size, as larger vessels such as Hive Ships have larger Queens. Evidence for this lay in the fact that, in numerous engagements, Swarm fleets seemed to lose cohesion in battle following the destruction of present Hive Ships, where each vessel operated more independently rather than as one unit. As a result of this, Hive Ships were often priority targets in engagements where they were present.

It was speculated that there was one overall, dominant Queen controlling the entire Swarm species, which would seem to explain the lack of visible leadership of the Swarm. Such a creature was postulated to be of gargantuan size to allow trans-galactic mental communication with all subordinate Queens. However, while many believed that the military was in possession of knowledge on the subject, officially such theories were never confirmed.

Constrictor
Completely external to the three-tiered Swarm system, the Constrictor had no known larval or adult forms; indeed, very little was known about them. Very rare within Swarm ranks, Constrictors shared very few visible traits with other Swarm types, leading to the common-held belief that the Constrictor was actually a separate species used by the Swarm. A powerful creature, the Constrictors were incredibly deadly, often used as war mounts and heavy infantry against almost anything on the battlefield. They were highly feared as a rapid threat able to engage infantry formations or armoured units equally effectively. Due to their near-unparalleled strength and comparative rarity, they garnered a near-mythical reputation among Theran, UNSC and Sangheili ranks.

Society
Swarm society emphasised a strictly hive-based existence, with each individual hive headed by a Queen. Within the hive each Tier had its own task and place. Hives were very compartmentalised and despite this, control is wholly centralised to the Queen in the central chamber. Swarm society was completely lacking in distinctions between military and civilian; in essence, the entire species was the military, with their entire society being based around making war and subjugating other species.

Other than these basic deductions on Swarm society, very little else was known about it, mainly as a result of the inability to study it in a nonlethal environment.

Technology
The Swarm utilised a potent combination of organic materials and inorganic technology, working in perfect unison. This gave extreme advantages over the more traditional technology used by the native races of the Milky Way Galaxy. Their technology was adaptable, regenerative and more enigmatic than anything even the most advanced UCG tech was, giving a notable advantage in various fields of combat.

Weapons
Swarm small arms generally consisted of a mix between Particle Cannons and railguns, and were generally more technological in origin than not. While these small arms were used by Harpies and Drones, forms such as the Reaper and Clackers did not use small arms. Tier 3 forms commonly mounted large weapons either directly onto their exoskeletons or through weapon mounts- bigger individuals were able to mount larger and more numerous weapons. Vehicles and warships used larger still weapons including mortars, energy weapon turrets, railguns and missile launchers.

Shielding
The Swarm, unlike most known races, did not utilise a sort of electromagnetic shielding. Instead, shields were operated by creating layers of energetic distortion containing a high concentration of gravitons around the protected area, in a very similar way to Allegiance shields. This was several hundred times stronger than more conventional methods and was far more efficient at dissipating highly focused energy or kinetic impacts. In addition, graviton-based shields were invulnerable to ionised weaponry unlike conventional models.

Armour
Swarm body armour did not exist in the traditional sense; all Swarm types had exoskeletons of naturally occurring carbon nanofibre, supported by an underlay of an organo-metallic polymer. This armour varied from thin layers, for example with Harpies, to very nearly impenetrable thickness, as was the case with the Tier 3 forms. As a result of this, additional armour was very rarely needed, as the forms already had the level of protection they needed. However, it was uncommon, though not unheard of, for large beasts such as Tarantulas and Trolls being equipped with extra armour plates before going into heavy fighting, similar to appliqué armour for tanks.

For armoured vehicles, warships and some ground-based hives, a synthetic/organic armour was used to provide protection from hazards and attacks. Swarm armour consisted of a type of semi-organic ceramic compound, underlayed with naturally occurring carbon nanofibre layers. This was often reinforced by a layer of some sort of metal alloy, its composition unknown to the inhabitants of the Milky Way Galaxy. This was supported by a layer of biological polymer similar to polysaccharides, but containing organo-metallic compounds. The finished result was an armour setup that could resist some of the harshest and most intense bombardments, almost to the degree of ERA/ACE Armour used by The Royal Allegiance.

Starships
Swarm starships were large, semi-organic creations enhanced and augmented through more traditional technology. Offering control similar to an in-built AI, the organic element of the vessel could be commanded as a separate entity, essentially being the vessel's overall, semi-autonomous, control centre. The level of intelligence that these vessels themselves possessed is still unknown, however it was confirmed that they have more than a non-sentient level of thought. Ultimately these vessels are controlled by beings known as 'Queens'- following the belief that each vessel is similar in organisation and operation to a ground-based hive. Queens were Tarantulas that were physically and mentally connected to the ship's consciousness. The Queen in this way controlled the vessel, the two sharing a symbiotic relationship in which the two minds merged on various levels of thought. The vessel's organic properties enabled a limited ability for healing and regrowth. It was noted that no two Swarm vessels, even of the same class, would ever be completely identical, despite sharing outward appearances and functions. This made boarding on the part of the UCG especially treacherous. The method by which these vessels were built, grown, or otherwise created, was not discovered during the entirety of the war.

Swarm vessels were noted for focusing themselves on heavy anti-ship weaponry, leaving their own defence against single ships to their huge starfighter complements. This made for a powerful setup that caught the Allegiance off-guard during the initial battles with the Swarm, though also left Swarm warships vulnerable to starfighter attack once their fighter screens had been neutralised.


 * Swarm Frigate- Swarm Frigates were small, fast warships designed to support larger vessels in battle. Although they lacked strong shielding or thick armour, they made up for this in speed and agility. Equipped with a modest armament, its weapons focused on destroying small enemy warships, and featured little in the way of anti-starfighter defence. However, the Frigate boasted numerous heavy Particle Cannon turrets and a large quantity of starfighters to compensate.
 * Swarm Destroyer- The Swarm Destroyer was a well armoured, fast and moderately armed vessel intended to strike at enemy warships. If featured a large starfighter complement, unusual for a destroyer, though this was in part to balance out its poor point defence complement. The Destroyer was often seen escorting larger vessels or operating lone long range strikes into enemy territory, or patrols in friendly space.
 * Swarm Cruiser-
 * Swarm Carrier- The Swarm Carrier was a very large warship that could carry thousands of Swarm starfighters into battle. It was well protected by shielding and armour, and featured a large complement of heavy weaponry. However, it was exceptionally slow and unagile, and relied on its vast single ship complement for adequate defence from enemy starfighters. It was commonly used in large fleet engagements to establish a dense starfighter cloud to protect other Swarm ships from enemy fighters and bombers.
 * Swarm Hive Ship- Swarm Hive Ships were very large capital ships used by the Swarm. Featuring immense levels pf shielding, armour, weapons and fighter complements, Hive Ships were the most powerful and well protected Swarm vessels encountered during the war. In spite of this, they were almost never sighted without a large accompanying escort fleet. It was largely believed that the Queen of a Hive Ship ordered the rest of the fleet's Queens, and as a result their vessels, through mental communication. Among other reasons, this was believed as on numerous occasions, once any present Hive Ships had been destroyed, the remainder of the Swarm fleet seemed to lose cohesion. The first known example of this was at the Battle of Chiaras.