"Them"—the enemies of Star Warfare. These enemies are mainly insect-based and come in many varieties. In the game, their purpose is to collect Mithril and destroy all in their way. However, some authors have chosen different backgrounds to the aliens' nature.
Armando Commando's Interpretation
Rise of the 901st SS: Dawn
In this incarnation not much is known about the origins of the alien invaders besides reports of being found consuming Mithril. However the purpose of such behavior is largely unknown, despite speculation that extensive consumption of Mithril by aliens transforms them into larger, more powerful behemoths known as "Maelstroms", which include Poison Pit, the Double Rages, Serpent and Siegfried.
Lieutenant General Miles Jagdtanker of the 901st leads D.C. Team, his personal fireteam, onto a space station gone dark. It is revealed aliens devoured the crew and left no survivors, and D.C. Team kills a large number of aliens in one of the first encounters between the monsters and humanity. The team are later evacuated by the UHAS Relentless and are later shown to suffer negative side effects from exposure to alien acid, such as dizziness, spontaneous fainting, and loss of concentration. Fortunately Alliance scientists are able to engineer armor upgrades by studying captured alien specimens, which are then distributed to all Alliance forces on UBW to protect them from alien acid.
Using Navy Flotilla 14, the Alliance attempted to destroy the massive alien swarms advancing North through the Great Plains, but suffered massive casualties to conventional and special operations units. The 901st and Seal Team Atom were mentioned by Captain David Radsworth of Navy Flotilla 14 as having lost large numbers of operators. Shortly thereafter the Alliance retreated their survivors and remaining military hardware to the stronghold of New Paris, located on high ground north of the Boreas Canyon through which the alien armies were advancing. Lacking tanks of their own, the Alliance quickly conceived a defensive strategy which combined snipers on rooftops, conventional troops in the street defending prepared kill zones with rifles and heavy machine guns, and rocket cars in the immediate rear to provide artillery support. While the sheer momentum of the alien advance managed to push back the defensive line and isolate numerous sniper teams on rooftops, the GIGN, Delta Force and 901st SS worked quickly to evacuate the snipers and kill more aliens. The strength of the Alliance-French defenses eventually forced the aliens into retreat, and special operations units and aircraft pursued the monsters out of the city.
After the Alliance successfully defended New Paris the alien armies were forced to retreat south of the French territory and regroup. Alliance leadership on Earth immediately began mobilizing armored units and special warfare attachment groups ("SWAGs") to reinforce Alliance positions on UBW. Alliance cities in the south of UBW quickly consolidated their resources and built up their defenses as aliens swarmed the surrounding territories. Meanwhile the alien master summoned the Maelstroms from off-world to assist the invasion effort. The comets containing the Maelstrom caused a degree of urban damage but were otherwise ignored. Serpent landed in Stadium Arcadium in New Leningrad and slipped underground shortly after landing.
Rise of the 901st SS: Maelstrom
The Alliance attempted to prepare for the aliens by sending military teams from various units to Saturn's moon Titan, in a week-long series of simulations designed to prepare them to combat the aliens. Sometime in the middle of the simulations, on UBW the aliens launched another offensive aimed at New Leningrad, located in the tundra of the Russian territory. Russian ground forces held their defensive positions with their own Misha tanks. The Russian armored units were assisted heavily by Spetsnaz units Alfa and Vympel, lead by Commander Ivan Tretyakov. When the 901st team sent to the Titan simulations returned to UBW, they were redirected to New Leningrad to help the Russians. They were joined by the Hyperion tanks from the Alliance, which had been recently relocated. Lieutenant Colonel Veronica Nikolayev personally killed Poision Pit, earning her the admiration of the Spetsnaz and Commander Tretyakov. Serpent also arrved and destroyed several tanks and gunships before retreating underground. New Leningrad was eventually liberated from alien infestation.
In a scene from the point of view of the invaders it is revealed that these aliens (or at least their leaders) have intelligence as shown when Sigefried and Serpent began to confront each other due to the dragon's inactivity in the invasion of UBW-594244. The dispute soon turned into a fight between the two titans before the the Master of the aliens intervened.
Lord Steelblade, commander of the Panthers, is also shown to have limited strategic competence as shown when he massed upwards of fifty thousand aliens in a large-scale offensive on Trinity City, the UBW equivalent of New York City located in the planet's American territory. The attack was in response to the Master's scornful rant that the aliens were failing to achieve any degree of success against the humans. At the same time of Lord Steelblade's assault on the city, an insurgent organization known as the People's Army of Independent Liberation mounted an attack on Navy Flotilla 14 and Trinity City. The attack on the Flotilla 14 prevented Alliance reinforcements from reaching General Jagdtanker's besieged battle group, and as such the aliens were able to advance deep into the society. The alien assault caused mass pandemonium and the military rushed to evacuate the civilian population. PAIL also inflicted moderate casualties on the Alliance soldiers.
After PAIL had lost a substantial portion of its air force and commandos in their attack, they retreated with a stolen Alliance cruiser in tow, the UHAS Fair Winds. Rebel commandos on the ground retreated after a failed attempt to destroy the Alliance hardware stored in Trinity City. Alliance engineers were then able to safely insert and repair the damage to generators that powered the city's defense systems. After repairing the generators, dozens of defense turrets tore out of the ground around Trinity City and shredded the alien invaders. Shortly afterwards Navy Flotilla 14 arrived and commenced an aerial bombardment of the aliens, massacring the monsters and forcing Lord Steelblade into retreat. The Battle for Trinity City concluded with the Alliance hunting down surviving alien stragglers still inside the city. Thousands of alien corpses surrounded Trinity City.