I know the Warhammer 40K universe doesn't really have good guys, but Chaos are definitely the bad guys, flying bastardised Imperium ships in service to unspeakable space-things. Their twisted, skulled battleships mutate to reflect whatever Chaos god they're flying in service to, bringing different buffs to the fleet.
It's a good thing too, because Chaos tech is a little out of date. They're more fragile than Imperium ships, but compensate with greater range and zippy engines. The instantaneous Stasis Bomb is a fittingly evil support gadget too, freezing the enemy in time while your own ordinance sails merrily into them.
I've been impressed with everything I've seen in the trickle of details Tindalos Interactive is letting out. Whether it handles like a strategy game using the Warhammer licence should—particularly with the promising Total War: Warhammer on the horizon—we'll know come March.