OK, so this is my problem. A friend of mine, who is also a player I'm DMing is the kind of person who loves to cause tension between the party members and provoke conflicts. I talked to him and he says that causing problems between the party is good roleplaying because every group has its problems, I told him that those problems appear by themselves and there's no need to provoke them, he disagreed with me and ended the discussion. In my campaign, a player wants to be a flyerspawn psychic, the conflictive player will probably end up killing the other player's (he kindda told me that) character once it becomes a flyerspawn psychic. So, how should I face this problem?

P.D: He's not a bad person, there was actuallt two or three cases in wich he had all the rights to kill another party member and he did'nt, but the constant search for conflict is not good for him and it wont be good for the campaign (he did'nt do anything yet... YET).