Killed the guy without talking to him, shot one of his guards so it didn't prompt the conversation.
Now every time i attempt to exit the castle or visit the upper floors of the castle it stops responding after the load screen, giving me a black screen.
(tried the upper exit, front door. Sewer exit)
I could enter the sewer area, but once i tried to load out of the sewer area into the world it would hang there too.