Son of the woman who Tsubasas father is dating. Hes a member along with the minor characters Martin Joker Ushio and Atsuya of an indierock band called quotYin amp Yangquot Because of his bleached hair and skull jewelry he is initially looked upon with suspicion by Tsubasa. Because he wants his mother to be happy and eager to have a little sister he has no objections to their marriage. However he makes the mistake of assuming that Tsubasa is an elementary school student due to her short stature causing Tsubasa to have a spectacular meltdown. Tsubasa is in fact one month older than Kazuma. His appearance consists of bleach hair and skull jewelry. It usually gives people the wrong impression of Kazuma. He is voiced by Akira Ishida. Kazumas most valued treasures are Tsubasa and his music. He slowly comes to terms with the fact that his love for Tsubasa is so much more than brotherly affection. And also with the fact that music will eventually drive him apart from her...