Matsukaze is a doll possessed by an unknown spirit and serves as the constant companion of Reiha, acting as a surrogate father figure to her. He is openly hostile toward Miyu, the vampire princess and guardian, and often uses his brash, rude, and insulting manner to berate her and undermine her position as the Watcher. Unlike Reiha, who expresses her hatred more subtly, Matsukaze is quick to anger and makes no effort to hide his contempt. Miyu regards Matsukaze as a separate individual, but Reiha does not share that view; Matsukaze himself claims that he and Reiha are one. He does not possess many overt powers beyond the ability to speak and exhibit his own personality, though he demonstrates the capacity to generate ice, which he uses during a confrontation to trap Larva, Miyu's companion, in an ice barrier so that Reiha can fight Miyu. In the final confrontation, Matsukaze sacrifices himself to protect Reiha from Miyu's flame attack. His primary motivation is to serve Reiha and channel the hostility and anger she holds toward Miyu, acting as a vessel for those emotions.