She is also called The Crimson Blade. Himari is a cat demon that played with Yuuto during his childhood when he stayed at his grandparents house. She can change her form from human to cat, even halfway, having a human body but with cat ears and tail. One of Himari's ancestors were spared by an Amakawa demon slayer, and so the ancestors and the descendants serve the Amakawa family. Himari has loved Yuuto since his childhood and she often flirts with him. Himari was sad when his parents took Yuuto away without saying goodbye. Himari is afraid of water where her feet does not touch the ground, she is fine with baths and shallow rivers. She took Yuuto back to his late grandparents house so that he can regain his lost childhood memory. She was able to help Yuuto get some of his memory by changing into her cat form. When Yuuto was seriously injured by the air demon Shama, Himari went into a berserk rage and was stopped by Yuuto when he was finally able to use his demon slayer ability of light. She faced off against Kuesu in Chapter 19, and was forced to retreat, losing her sword in the process. To mend her wound she ingested a drug that reverted her to her neko-mode and stripping her of her sanity and acted like a cat. (Source:Wikipedia)