Allow an evil cleric and other evil characters??

[Jezrael]

Why not?

I'd say if he wants to play evil let him. Remind him however that all of his actions may have consequences, one of these being that his current party may eventually want to schwack him for truth, justice and the Faerunian way.

I allow evil characters in my campaign because my players know how to distinguish between a characters actions and a players; we're all very mature about the whole thing and have had no problems.

One thing to watch out for is the "You killed my character so my next character automatically hates yours and will try and kill him/her" syndrome, nothing will stop a game quicker than an ever escalating revenge competition betwen players.

 

[Bastoche]

This seems much more problematic. If I get it well, the player doesn't want to play an evil character per se, he wants to casts evil spells. Being neutral may just be enough. And of course, a Tyr follower won't accept that kind of spell usage for too long. Maybe that player should have played a sorceror or a wizard...