The last time we saw Durkula before the last few strips was when Belkar stabbed him in the heart with a wooden stake. It was enough to "kill" the vampire so that Durkon's soul was finally free.

Questions:
1) If a vampire inhabits the body of a previously living host, then who's body is Durkula in? And who's body is Durkon in?
2) In AD&D is a vampire defeated when they're forced out of their host? Are they defeated when stabbed in the heart with a wooden stake?
3) How did Durkula come back? Or did he ever go?
4) How can Durkula be defeated if he doesn't need a body?