Well, while I'm very tempted to think that Joric and that entity he's playing host to may have malevolent intentions, I'm open to the possibility that it's just a red herring and that he's actually not that bad a guy. As for the earthquakes, I'm thinking that it isn't natural in nature; there's somebody or something doing a lot of digging under the keep. For what reason I don't know, but to me that makes the most sense to explain that much unusual and sudden seismic activity. That or the keep was actually built on top of a volcano and we're about to get Pompeii'd.