Ushio Toujou
Toujou Ushio is Mimi's classmate, also known as member of “mecha mecha mote te ru mondaiji sannin gumi” or MM3 by Mimi. He is in the athletics team, but refused to take part in the marathon. Mimi took up the challenge of making him taking part in the marathon by having a race, and in the process, both of them developed feelings for each other.
He is actually the one Mimi fell in love with in junior high school, but she confessed to the wrong guy!