Can something like a helghast from killzone fit in to this group? Or at least guts from berserk as a warrior of equestria?

Not too sure....

2427255 If their soldiers then they can go in the "Military" folder(I never played Killzone) and though I haven't seen Berserk, you can add Gut's you just have to figure out which folder he belongs in.

2427507 the berzerker folder.

2427785 Then by all means add em