In the Chronicles of Nick Books by Sherrilyn Kenyon, are Dark-Hunters good or bad and is Acheron good or bad?

I've read the first and second Chronicles of Nick books, and im still not sure if Dark-Hunters are good or evil. Nick is warned that Acheron is bad, but is he really or is it a mistake. Cuz Acheron seems like a nice guy, and he's part of the Dark-Hunters.