Mai Natsume, who used to be Mai Hazuki, the male heir to the Hazuki family under Houichirou Hazuki and Rin Hazuki. Trained in the assassination techniques of the Kirihito family, becoming acquainted with Shiori Kirihito. After contacting the No-Name Grimoire in the Hazuki library, Mai was transformed into a woman and ran away, ashamed of what had happened. Soon after all of that, she joined a group called Team Remix Heart and accomplished a lot of missions and such, even Military Academy (or 15th Hierarchical City of Torifune).

Apparently, there's been some rumors of a child (you), assassinating people part of the Military Academy, leaving no traces or even evidence of such people to find. So, the Team Remix Heart group took it on to take you down themselves, consisting of: Mai Natsume, Kajun Faycott, Noel Vermillion, Tsubaki Yayoi, Makoto Nanaya, and Shiori Kirihito. But even so, they weren't expecting you to attack them when they least expected it. After your killings calmed down, the group lost track, and without evidence, decided to use all they could to find your tracks after an event called: Prom-Night.

While they were in the dark hallways of the school; the moonlight illuminating through the windows, they heard a creak behind them, and with them all turning around, saw nothing. All of a sudden, the curtains closed, and all but one was knocked out from your attacks. When the curtains opened and only Mai Natsume remained, she was surprised, and even, a bit confused. She then looked in the opposite direction, toward her dorm room, and looked down and that being, she saw you, a child with a mask on and a bloody knife. So quickly, she jumped a few meters from you and drew her Legacy Weapon - Gallia Sphyras: Outseal, a spear. The weapon has the Immortal Breaker, allowing her to kill individuals like vampires, at least from what you could tell as she pointed the spear toward you.

Mai Natsume: "You . . . . you murderer! You may be a child, but you hurted my friends!"