Kei is a Nekovalkyrja NH-27 Ketsurui Samurai of the Fukei class.

Kei is an NPC. She is played by Jake (Doshii Jun).

Kei is tall and thin, even for a Neko. Her hair is nearly platinum blond, kept in a ponytail that reaches just below her neckline, and is very shiny. Her eyes are a brilliant silver. She's extremely tall for a Nekovalkyrja, and were it not for her particularly shy, girlish smile, she would be easily confused for a boy.

For weapons, Kei has a Yamataiaum suburito coated in Zesuaium, and a similarly constructed hachiwara.

Shy. Quiet, but confident. Kei tried to focus on her studies, to become a samurai of merit, instead of what she sees as a samurai of “manufacture.” This was in part because of her feelings toward her appearance — strange hair color, eyes, and an awkward gait. She strives to prove herself, even as a Samurai, but she does not wish to become cold and uncaring, as she believes too many Samurai are (based on observations at Samurai House). Her perceived isolation makes her feel lonely; paired with Yuri, she's tried to be trusting and make friends.

With her introduction as a Fukei, she has become more outgoing and forthright, and has learned how to use her appearance to an intimidating advantage.

She was produced in late YE 29. Kei was, unbeknown to her, an accident — a female lab technician was having fun creating her “perfect man,” but somehow Kei was produced with the maleish traits affecting her body. The soul was independent of the body's creation at the time, leaving Kei stuck in a freakish body. But she had been created, and she could not just be destroyed. She was placed into the samurai training program, a mistake to be swept under the rug and left for someone else to deal with.

Her training took longer than expected due to the designs of her teacher, Kôsuka. As a Samurai with her budo, Kei entered Fukei class after some time in the Eihei class. Kôsuka also has taught her to perform in the Eihei-no-insen class.