With the dicsussion lately about the Den of the Fallen (I got this on my first play through, and didn't think to post anything about it) I figured I would shine some light on a rare mob in the Cathedral.
Lloigor is a crazed Conjuror pouring through the libary in the Cathedral. When he appears, it is always at the begining of Lvl 4. He will be standing on the far side of the libary reading from a podium. He is "friendly" until you touch the podium, at which point he'll get rather upset and start conjuroring bats to throw at you.
This is a purple type boss, so he has a reasonable chance to drop some loot, and wouldn't you know it, he dropped a rare while I took pics for the article.