Veer-Myn
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The Veer-Myn are evolved mutant descendents of rats that stowed away on human ships for centuries, and now plot against those above in Warpath. They have access to mutant monstrosities, and Big Daddy-like rats who've played too much BioShock. They can be aesthetically summarized as "Space Skaven" (they actually are called "ratmen" in-universe). Their main tactic is to stow away on a ship, create a colony on whatever planet the ship arrives on, slowly make the colony bigger until they're ready to take over the world, stow away on a fleeing ship, create a co...
They'd be great Skaven proxies for a Warhammer Fantasy army, if it wasn't for the sheer amount of guns they wield.