Mizuki is a friend of Yukimura, first introduced in a flashback in volume 11. She wishes for her father to be less protective of her and her mother. It is strongly suggested that Mizuki and Yukimura were developing feelings for each other. Yukimura promises to protect her, but on the same evening, Tokugawa attacks the city, and Yukimura fails to save Mizuki. Before dying in his arms, she gives him her father's sword and correctly predicts that he will grow stronger and that there are people who need him.
Her death triggers Yukimura's inner "dragon" to awaken, transforming him into a fierce "demon" who punishes evil. Even twenty years after her death, Yukimura and Saizou still mourn her, and Yukimura continues to carry the sword she gave him.










