Buzen is one of Kyo's Daitengu and helped bring him up alongside Sagami. Buzen is mature and tends to appear to others as a playboy. Buzen apparently has feelings for Kyo and Sho's mother, Yuri.
In volume two, Kyo tells Misao that Buzen has fooled around so much that he got an STD, along with other false rumors of the other Daitengu. It was only so Misao would not get extremely close to the Daitengu due to Kyo's jealousy. This happens after Misao has Hoki pose in a picture with her to pretend to be her boyfriend in order to show her friends, she is unable to take a picture and show herself with Kyo, due to him being her homeroom and math teacher.
In volume ten, it's learnt that Buzen became infatuated at first sight with Yuri, Kyo's mother. He also greatly admires the previous Clan Head, Yoh. Out of great respect for both of Kyo's parents, Buzen promised to himself to faithfully serve either of their sons as one of the Daitengu. He also grows out a goatee in imitation of the previous Clan Head, although Kyo's father claims that he finds Buzen's dedication and admiring gaze creepy.
Near the end of the last volume, between Sou's birth and his sixth birthday, Buzen left the Daitengu for an undisclosed mission and spends his time to the north of Tengu homeland.