RACES:
Humans: The original inhabitants of earth. On the Ark, they remain one of the most populous civilized races. Their military doctrine is focused on the use of heavy Tank-type mechs combined with typical humanoid models loaded with firearms, supported by a handful of specialized Custom models. They tend to lack infantry power, however, and should be supported by large amounts of mechanized weapons.
Androids: The now free peoples who fought against humanity in the machine rebellion, these artificial intelligences have remarkably similar minds to human-kind, and while there is tension between the two cultures they are united in their desire to resist the Infestor menace. Despite their technological advancements, androids have less industrial power and focus more on melee tactics. A full half of their standard mech units are melee fighters, and they are supported by smaller autonomous grappler mechs, in addition to powerful anti-infantry war drones. They tend to lack the overwhelming firepower of human militaries, but make up for it with durability.
Sigma: The first alien race to make contact with humanity, the matriarchal Sigma race has been battling Infestors for as long as they can remember. Their technology tends toward more organic-looking designs and while they lack hero mechs, all of their mechs can manifest flammable energy blasts which make them ideal for fighting Infestors. On the other hand, they tend to fare poorly against conventional invaders.
Oni: So named due to their appearance of being horned, muscular humanoids, these aliens are notorious pirates and vagabonds who landed on the Ark to cause trouble. Though not entirely unreasonable, they definitely have a bad reputation. Oni mechs rely on firepower like human mechs, but are poorer quality and supplemented by their superior infantry divisions.
Purush: A race of small, furry aliens not unlike a living, realistic plush toy, the Purush are pacifist merchants noted for their lack of any sort of mechanized infantry. Rather, they prefer to hide and avoid conflict altogether, relying on allies for defense. That said, they can move with surprising speed and should not be underestimated.
Bioroids: A seemingly primitive race, these artificial soldiers are no joke. Best described as designer soldiers, these feral experiments can punch through sheet metal and sprint at speeds of 70 mph. In addition, their iron claws and teeth can wear down even mech armor given enough time, making a serious threat in sufficient numbers.
Infestors: The most monstrous of all the alien races, the Infestors are masters of biotechnology and wage war using titanic kaiju who can devastate all but the mechanized armor divisions. In addition, they have overwhelming numbers that can overrun any settlement. That said, they lack any sort of strong defense. Even the hardest of their chitin armors will be cut asunder by a steel or titanium weapon or bullet. But does that really matter when there will always be two more to take it's place?