He´s the younger brother of Kazuma Yagami and son of Genma Kannagi. He shows a love beyond any imagination for his brother and admires him no matter if he is or not able to control fire. He shows to be really mature and pure hearted and will do anything to protect the ones he loves. His fire power, the golden flame, can purify demons and evil spirits with great ease. He is frequently used by Kazuma and Ayano as some sort of puppet or bait. He´s very popular at school and his best friends are Serizawa Tatsuya, a tall and athletic guy, and Suzuhara Kannon, who has love feelings towards him. In the story he takes more relevance during the Tsuwabuki episodes, were he meets a girl from his age, Ayumi Tsuwabuki, and falls for her, later he discovers that she is some kind of clone created as a sacrifice for a ritual to keep Mount Fuji under control and makes the impossible to save her from that destiny, but even after stopping the ritual she dies after telling him that she also loves him. This event makes him grow and decides that he will use his powers to keep the ones he love safe.