Yamaka

is a high school student who attends Saint Ishiyama Academy. He has participated in the school's special event, Saint Saint X'mas, with a fellow high school student, Koyoshi.

Saint Saint X'mas Arc
Yamaka and Koyoshi participate in the Saint Saint X'mas competition together where they advance to the Top 16. In the first round, they are selected to go twelfth, pairing off against the Nishizawa-Yonehara pairing; ultimately, they end up losing in the first round.

Koyoshi
Yamaka and Koyoshi participated together in a Saint Saint X'mas competition on Christmas Eve.