[quote=@Raineh Daze]
I think you've got it backwards. Heroic characters will, by definition, be disinclined to work with the blatantly evil psychopaths than they are people who were just antagonists [i]in general[/i] in their source material. I wasn't talking about making characters that will be antagonists in this game as well.
[/quote]

Well, I didn't meant blatantly evil psychos as well. I mean something more in the camp of pragmatic villains that are willing to go the "enemy of my enemy" route. These types are less likely to be antagonistic when the situation calls for it, even though they would gladly break apart from the heroes when given the chance.

I hardly think of complete monsters as villains instead of plot devices that need to be deal with in some way or another, so that's the the cause of the confusion. Just like antagonists usually mean not just characters that do evil deeds or other villainous things but types like rival heroes and such as well, anyone that would get in the way of the heroes, really.