Malicious, will make all efforts to destroy intruders.
Thalas, the royal alchemist, was sentenced to be locked away, after his part in the conspiracies against the pharaoh. You can camp this monster by summoning DS to absorb the towers shots and staying in the south of the room.
He will attack with distance magic attacks, so use blockers to corner him and distance fighters to fire on him. He is guarded by 4 Necromancers and 12 Plaguethrowers (6 around Thalas and 6 more near the teleport).