By the time he is introduced, Sumiya Mega has taken a break from his club activities due to a personal injury and seems to know more than he lets on about Asou's situation.
It is heavily implied later that the injury he received was suffered when "proving his love" for Yuuko Kirishima. He is aware that Reiko Asou has feelings for him, yet still chooses to pursue Kirishima's attention.
The club that he belongs wasn't revealed and it is unknown if the love triangle he was involved in came to an actual result.
- Kirie described him as "unsightly" and mentioned that indecisive guys like him never bring any happiness.