Swarm War

The Swarm War, also known as the Black Century and the Great War, was a devastating pan-galactic conflict that arose after The Swarm, a violent insectoid species, invaded the galaxy. The war engulfed the entire Galaxy for a span of 145 years, during which period the Swarm slowly but unstoppably pressed nearer the galactic core, invading and capturing their populations and leaving a trail of razed planets in their wake. The Swarm, dependent on organic hosts for survival and masters of biotechnology, overwhelmed the combined efforts of the UNSC, the Alliance of Sangheili Clans, The Order and The Royal Allegiance, emerging victorious from battle after battle due to superior tactics, efficient biotechnology and sheer numerical superiority. Although the Swarm War began in earnest in 2733, in actual fact first contact occurred on the planet of Radiance in 2614, a remote colony on the rim of the galaxy. The Swarm wiped out the population and then left, leaving no trace of their nature remaining for the colony's discovery nine months later. The Swarm observed the galaxy for a over a century before launching their all-out assault, slowly encroaching into the heart of the galaxy. The war cost the lives of over 300 trillion sentient beings and devastated or destroyed over forty million worlds. The galaxy did not recover from the Swarm War for at least a millennium after the defeat of the Swarm, though some historians believed it did not recover fully at all. Thus, the time before the Swarm War was referred to as 'The Golden Age', as a time like it was never truly achieved again.

Origins
The origins of the Swarm War lie mainly in the Swarm's reliance on organic hosts for reproduction. Incapable of producing offspring on their own, their reproduction was dependent on implanting genetic material and fertilised eggs into (preferably living) host beings. The Swarm had travelled millennia between galaxies from their home one; their reasons for this mass exodus are still unknown, though speculation points to the depletion of that galaxy's prey species. Surviving in stasis with a few select individuals known as 'Keepers' watching over the vessels, the fleet of billions of vessels arrived in the Milky Way galaxy weakened and in need of both life forms for reproducing and food, the Swarm encountered several uninhabited planets, wiping them clean of animal life, before coming on the Allegiance outpost of Radiance.. Over the next hundred years or so the Swarm remained in the shadowy realm on the periphery of galaxy, consolidating their strength and preparing for the galactic invasion to come. The Swarm's ultimate intentions in the galaxy seem to have been to consume all it could, leaving the galaxy devoid of life while growing themselves in strength and numbers, before moving on to another. It is unknown how many times previously the Swarm had journeyed between galaxies if at all.

On the other side of the conflict, all the major factions of the galaxy were drastically cutting both their military spending on operational units and development. This was partly because of a widespread economic downturn, and also as a result of a new era of peace that negated the need for massive militaries, which had arguably been necessary since the end of the Human-Covenant War. The war with the Covenant Remnant lasted until 2559. which was followed by at least a century of instability, constant skirmishes and military escalation. Rebellions, civil wars, insurrections, genocides and other events all dominated the known galaxy until at least 2620, with their gradual decline in the following decades. All factions took the opportunity to slash their military spending, and by about 2700 conflict was very rare and armed forces were a fraction of their size in the preceding century. The galaxy's prosperity at large picked up noticeably and quality of life for all sentient species improved; however this left most nations vulnerable and the galaxy wide open to attack from the Swarm, who were waiting for such a turn of events from afar.

Belligerents
The Swarm War was the first to see all known races of the Milky Way Galaxy unite to face a single foe, although this did not occur right away. The war saw several large and numerous smaller factions all pitted against the Swarm, which was numerically superior and arguably technologically so in addition to this. Despite being technically part of one united faction, the various nations did not cooperate to a large degree until the scale of the Swarm threat became clear, and operated as allied, though separate, entities. Following the formation of the Unified Coalition of Governments Armed Forces in 2785, the allied nations began interacting much more intimately with each other in terms of strategy and coordination, improving to some extent the battles with the Swarm but doing little to change the tide of the war.


 * Alliance of Sangheili Clans- The Alliance of Sangheili Clans was the governing body of the Sangheili race. It was formed a few days after the Battle of Installation 00, out of the Covenant Separatists. By the time of the Swarm War the Sangheili encompassed several million worlds, many with multi-species populations. During the war, the Sangheili's military was near constantly active against Swarm forces, not only in their space but in other territories as well. Sangheili space was heavily encroached into by the Swarm, with heavy civilian casualties and planets lost. In particular, the Sangheili as a whole could not understand the Swarm's constant hunger for sustenance or its violent hive-based society, and therefore did not meet them on the battlefield with the same respect that they had for past enemies. The Sangheili and many other former Covenant species shared an extremely close bond during the war, with the possible exception of the Jiralhanae-Sangheili resentment, and all referred to the Swarm most commonly as the abomination, in a similar manner to the Flood.
 * Democratic Unggoy Alliance- The Democratic Unggoy Alliance, or DUA, was the ruling body of the Unggoy species. Seeing the Swarm threat, the DUA began to fortify their worlds and prepare for the Swarm's attack, rather than pro-actively involving itself with the war before it had reached their borders. When the Swarm reached their doorstep they quickly overwhelmed the Unggoy's defences, devastating the DUA's civilian populations. From this point on Unggoy forces, spatial fleets in particular, played a more prominent role in the war.
 * Kig-Yar Republic- Despite not being directly in the line of attack during the early years of the war, the DUA saw that the Swarm was a major threat and as a result, actively involved itself with combat. The Kig-Yar's vast fleets of fast, light vessels were most commonly seen aiding UNSC and Sangheili forces in various battles though operated more or less independently in the Kig-Yar's own attacks on the Swarm, which it mounted frequently during the war's first century. The Kig-Yar Republic, however, took heavy losses when its territory was invaded despite large scale preparation and support from other allied factions. From this point on the Kig-Yar's role in the war was diminished but not insignificant.
 * The Swarm- The Swarm was a vicious extragalactic insectoid species that depended on organic incubators for reproduction. Coming in three known life stages with various different forms, the Swarm besieged the known galaxy with massive numerical superiority, stunning tactical moves and advanced biotechnology. The Swarm, although taking colossal losses before the end of the war, never really seemed to be affected by this, mainly due to its huge relative size. The Swarm entered the galaxy on a vector taking them through Allegiance space, once there exploiting neutral zones and assaulting and eventually breaking through to other nations.
 * The Royal Allegiance- The Royal Allegiance was a technologically advanced faction of near humans, or Therans. Despite inherently despising war the Allegiance maintained a substantial and modern armed forces as a result of centuries of turmoil following the Human-Covenant War, although these numbers were slashed in the mid 27th century. Bearing the initial contact at the Antaeus Nebula as well as most of the first attacks, it was the Allegiance that discovered the true extent of the Swarm threat and surmised that they could not deal with it alone. Being the largest faction in terms of territory, the Allegiance took the heaviest losses in terms of military, civilians and actual planets fallen.
 * The Order-
 * Unified Earth Government- The Unified Earth Government, or UEG, was the ruling body of the Human race. Seeing major action during the Swarm War, the UNSC, the UEG's military branch, was the second force to engage the Swarm after the Royal Navy. Along with the Therans and the Sangheili, the UEG fought most of the Swarm War's battles and took the heaviest losses. The UEG played an important role in the eventual defeat of the Swarm. Although the UEG's territory was severely encroached upon during the war, hit-and-run and guerrilla tactics helped the UNSC survive when it was at its weakest.
 * Unified Coalition of Governments- The Unified Coalition of Governments, or UCG, was set up following the Human-Covenant War aimed to facilitate cooperation in galactic law and security, and the achieving of galactic peace. During the Swarm War it increasingly gained military control from its constituent nations, reluctantly handed over by them, to enable closer cooperation between armed forces. From about 2800 the armed forces of each individual nation did not exist and were instead dissolved to together form the UCG Armed Forces. In 2892, after the war's conclusion, the UCG amalgamated each nation into itself to form the first interspecies, interstellar government. The UCG's participation in the war was demonstrated through virtually every engagement that took place.
 * Union of Jiralhanae Tribes- After having a kind of epiphany after their crushing defeat after the Human-Covenant War, the Jiralhanae race had matured immensely and, despite still maintaining a somewhat strength-oriented society, they focused more on honour obtained through combat rather than combat itself- though largely recognised the futility of war for war's sake. Ceasing their destructive, often self-damaging, nature, the Jiralhanae slowly developed their society and saw the benefits of peaceful advancement. Being physically on par with many swarm types, the Jiralhanae saw very widespread action against the Swarm, both in their own territory and protecting others, particularly the UNSC, Kig-Yar and Unggoy. The Jiralhanae race saw the loss of their homeworld and many of their core worlds, and took heavy losses more specifically in ground combat, as races such as the Therans and Sangheili tended to operate the spatial defence while the Jiralhanae took the ground combat alongside the UNSC.
 * Yanme'e Conglomeration-

First Contact
The first confirmed encounter with the Swarm by any race was in 2614, when they happened upon the Allegiance outpost of Radiance. The colony was a relatively small scientific outpost on a frigid planet, isolated and largely unknown. Several Swarm ships assaulted the colony, and, while quickly smashing through the spatial defenses, were pressed into a short but bloody battle with Allegiance ground forces. Ultimately this proved futile and the Swarm overwhelmed the defenders, thwarting a desperate attempt to warn the Allegiance at large. The Swarm then moved on, having tasted the rewards invasion of the galaxy could bring and hungry for more blood. Following this, they slowly but covertly built up their strength, all the while observing conflict in the galaxy slowly weaken individual factions. The Allegiance did not discover the remains of the Radiance outpost until nine months later, by which time the Swarm were gone and would not appear on the galactic scene again for over a century.

Social
In terms of social impact, the Swarm War was remembered for many centuries following as a near-cataclysmic event. The War had a lasting impact on social memory. It was seen by many in the galaxy as signalling the end of the 'Golden Age', the name given to the period of relative prosperity and development preceding the war from the early 2600s until the start of the war. Many across the galaxy regarded the event as a watershed moment, in that the galaxy as a whole, regardless of species, had been presented with a potentially all-consuming enemy, the likes of which had not been seen since the Forerunner-Flood conflict. The commonly held belief was that such a serious, existence-threatening war threw the small conflicts and skirmishes between 2559 and 2620 into stark contrast, effectively shocking the galaxy into a deep-seated opposition to conflict, even in warlike races such as the Jiralhanae.

The social trauma caused by unprecedented rates of casualties manifested itself in different ways, which have been the subject of subsequent historical debate. The experiences of the war led to a collective trauma shared by many from all participating nations. The optimism 'The Golden Era' was destroyed and those who fought in the war were later referred to as the Lost Generation. For years afterwards, people mourned the dead, the missing, and the many wounded. Many warriors returned with severe trauma, suffering from psychological trauma. A lucky few returned home with few after-effects, however their silence contributed to the conflict's growing mythological status. In the Royal Allegiance and the UEG, mass-mobilisation, large casualty rates and the collapse of the colonisation age made a strong impression on society. Society post-war was burdened with rebuilding the galaxy's shattered worlds whilst coping with the loss of billions of sentient beings to a terrifying, seemingly unstoppable, all-consuming enemy.. This contributed to exceedingly low public morale immediately following the war, which lasted for several decades after the war. Despite the galaxy's new-found aversion to pointless wars between intragalactic races, now that an extragalactic one had forced them to unite, this discontent gradually grew until it was largely to blame for the Galactic Civil War between 2912 and 2951. Ironically, this war was more inwardly destructive than any other intragalactic conflict previously save for the Human-Covenant War.

The Swarm War became such a common term in every day language that, in the Theran language at least, it acquired its own character, as occasionally happened to represent phrases instead of spelling them out with traditional characters. This character remained in use until at least seven centuries after the war, though by that time it had lost its original meaning and instead was used as an analogue to what would be literally translated to ' the eternal darkness '.