The Space Aliens

The Aliens are the main antagonist of Earth Taken 1, 2, and 3. Alien Infantry, Alien Heavies, Alien Bombers, Alien Heavy Pistoliers, Mecha Aliens, Alien Saucers, and finally Leapers all appear in Earth Taken games.

It is known by many survivors that the dog-like Aliens called Leapers taste good, and many are seen being roasted on sticks in some select shelters across the games.

The Alien race used some sort of tactic to poison Earth's air, killing everyone with no sort of rebreather and killing all animals except the crows.

If Jonah's theory is to be believed, the UN struck a deal of some sort with the Aliens.

All humans on Earth seem to hate the aliens, apart from the few brainwashed by the Aliens.