Seijuurou Mikoshiba
The captain of the swim team at Sametsuka Academy.
He has a crush on Matsuoka Gou. It is revealed in the second drama CD that he kept framed pictures of Gou in his room and was writing a love letter to her. His crush seems to be one-sided, with Gou turning down his advances (e.g. refusing to go on a date with him and appearing to be disturbed by the fact that her pictures are all over his room).
He also has a younger brother.