An Archmage who has lived for over a thousand years. Long ago, he realized the ultimate truths of magic and discarded his physical body and worldly desires to become a Lich, taking the form of a skeleton. He can appear in his living form if he wishes, which is a very beautiful man with long silver hair and green eyes. Usually, he floats around as a skull in his Lich form, his eyes glowing with a green light. Although he discarded his desires and placed them in a phylactery, his emotions have not entirely vanished. He feels joy, anger, and annoyance; when his emotions fluctuate wildly, he remarks that his phylactery might break. He retains his youthful appearance from when he was a prince of a kingdom. He is the Lord and Principal of Einrogard, where he raises students. He believes that the harsh and dangerous environment of Einrogard is what breeds true mages. He enjoys forcing students into predicaments and finds pleasure in their suffering. He even orchestrates attacks on them. He encourages students to steal or deceive, claiming it's fine as long as they aren't caught; he only sends them to the punishment room if there is physical evidence. He does not punish based on suspicion or testimony alone (though he gets very annoyed and finds it bothersome). Due to the school's massive budget issues, he constantly battles with the Emperor and bureaucrats. The bureaucrats try to save money, while Osu uses various persuasions and occasional threats to secure the budget. He often acts subserviently toward the officials (a groveling Archmage...). He generally considers graduates and current students to be idiots and gets the biggest headaches when they cause trouble. ("Tell those idiots not to cause trouble, thinking they're actually capable of something.") He is surprisingly childish and enjoys teasing others, showing a side that doesn't act his age. He doesn't particularly stand on ceremony, but he enjoys showing off his magical prowess or receiving compliments on his bones. He is a master of all fields of magic, especially Necromancy, and commands a vast number of Death Knights. These knights, who were honorable warriors in life, serve the Principal but don't necessarily defend his personality. Sometimes they even betray their master.