Phillip IV
The son of Cassander. A known Lich. The Danger Gang recently met him. With a little smooth talking, he did not kill them outright, but has instead sent them on a quest to find a Bloodstone.
He has clearly been driven mad by years of isolation, and perhaps from reading the Al Aziz. He now hides in a room in Cassandrea, writing the letter mu over and over on top of all his books.
He has a pet cat that is possibly invisible, or maybe is a displacer beast, or maybe it doesn't really exist. He also has a pretty kick ass looking staff covered in rubies.
He seems aware of the impending fate of the world and has decided that his best hope is to hide out where he is, wait for the whole thing to blow over. I gotta say, it sounds like an alright plan.