Sensei [or Teacher] is the character that Shiki recalls and describes in his conversation with Sion. One of five true magicians in the world. The Sensei's real name is Aozaki Aoko. She gave Shiki the glasses that helps him suppress his Mystic Eyes of Death Perception, and is the only character that Shiki refers to as Sensei.” They say “she's the trouble maker from London” or “she's a great witch… but only when it comes to destroying things…” but rumors aside she can be pretty troublesome you know!?
- ^ Teacher.