“He really did become someone else.”
He’ll likely be Joker until he starts training for his next role. Then he will be that.
He is likely nobody himself. An empty vessel.
He’s not.
He’s a recovering alcoholic.
He’s a liberal now, but he gets a pass from me, because he’s a master.
If you choose to believe the stories his family were raised in some sort of cult. No doubt, that being in the cult did not do the man any favors psychologically.