Dorn in a Good Party?

Does anyone know what will happen if I keep Dorn in my good party? I remember playing that game when I was younger and i had Kagain(Evil) in my party. My reputation was at maximum (20?). At some random point, he just leave the party.

So now, I have Dorn, and I want to know approximatively what reputation I should have to keep him.

Also, I have Ajantis in my team. He didn't agree for taking Dorn (obviously). I there any chance they fight each other and one of them leave?

Thanks!