Hello and Welcome to the Chrons.
I think before we can help you, though, we'll need to know a bit more. A group of bad rogue CIA agents are going to have a different name from a group of religious terrorists, from a group of Greenpeacers gone mad, from dark elves, and from aliens who have beamed down from the mothership. Give us some idea of their composition and their aims etc and we might be able to come up with something.