the mc awakens in the body of leader of a powerful sect which is about to be married to a girl (who was supposedly was forced to marry him) of a different sect. Everyone fears him. But since he's "isekaid/reincarnated" in the body (can't remember which), he doesn't know how to fight or use his abilities so he acts kinds to those around him so he wont get in fights.

Supposedly the leader has a cruel personality, so people around him was taken aback by his new kind personality.