Mutsue Yasuri (鑢 六枝, Yasuri Mutsue) was the sixth head of the Kyotō school of Japanese sword martial arts, the husband of Migiri Yasuri, the late father of Nanami Yasuri and Shichika Yasuri, and the person that Togame initially sought for the mission to find the Deviant Blades.
Although Mutsue is a human, he thinks of himself as a sword. He believes that there is no meaning to a sword that does not cut, and furthermore, as a sword, he does not need emotions, nor to think, nor to feel anything.
Mutsue is a tall, muscular man with wild aggressive appearance, which can oppose his personality.
After killing Takahito Hida, Mutsue and his family were exiled to an uninhabited island in the country of Tamba. He is later revealed to have attempted to restrain Nanami's power and denied her succession to the Kyotō art despite his willingness to, not because of her gender or frailty, but because he was simply unable to raise such an exceptionally powerful individual, also noting that she had the same eyes like those of his father. After training Shichika in the Kyotō art to become his successor, Mutsue requested Shichika to kill him, which Shichika fulfilled.
Mutsue is a master practitioner of Kyotōryū.
- The name Mutsue means "six" (六) (mutsu) and "branch" (枝) (e).
- Mutsue's surname Yasuri means "file, rasp" (鑢).
- His full name literally means "Six Branch Rasp" altogether. His children's names represent flowers and fruit, products of a tree's branches.