How does Harry ultimately defeat Kravos?

Harry lays down to go to sleep, while imprisoned in Bianca's mansion. Kravos comes to him in his dream, and Harry provokes Kravos into choking him. Harry dies for a moment when his heart stops, but Susan does CPR on Harry's body in the real world, and brings him back. Harry was technically dead just long enough to create a ghost, who helps him kill Kravos. Harry turns into a wolf and devours Kravos, restoring his own magic and taking Kravos' as well.