Kai Nishida  

, 西田 甲斐

Kai is Risakis younger brother and the last member of the Drama Research Society. He was drafted into the club against his will by his sister, who also brought in Mugi at the same time. Despite not wanting to be part of the club, Kai and Mugi have an unusual friendship due to their shared circumstances. As time goes on, Kai develops romantic feelings for Risaki. However, he is frequently pressured by his sister to do things for the club that may harm himself.