These vicious looking baddies are some of the worst you could hope to encounter when it comes to an invasion. They are grotesque beings who have been coming and going from Earth since before mankind was fully realized. Their sole purpose seems to be to wipe us off the planet and they have gone great lengths to do so.
The Chimera have multiple forms, including Hybrids and Feral. With mixed tactics and the ability to use our own weapons against us as well as their own advanced weaponry, we would be in for a hard won fight.
They not only wanted to annihilate us in the Resistance series, they also wanted to convert us into one of them and use us as soldiers. Whether we fight and die or survive long enough to be converted, we can't all fight off the coming threat. They were also living on the planet millions of years before us, so they clearly have a "home field" advantage. Very dangerous.