Wataru Kagami

Ryousuke's younger brother, very cute and easy to mistake for a girl. He took up judo to be more like Ryousuke but broke his leg when they were sparring, prompting Ryousuke to quit judo. He's also friends with Kenichi, who sides with him when he implores Ryousuke to go back to judo. He turns out to have a crush on Kenichi, who seems to reciprocate.