 After his memory returns, he shows real regret when he can't undo the damage he did to Sam and essentially sacrifices himself to save him out of remorse for his actions.After Castiel wakes up from his catatonic state, he is now depicted as insane with tendencies to ramble about random topics.However, parts of Castiel's original personality are still shown with him still being happy to help Sam and Dean out and still knowledgeable about various supernatural things, but not willing to actually fight anymore even when his life is threatened.