Yosuke is a clumsy transfer-student who arrived six months before the protagonist. He is often the target for jokes about his lack of muscles and body strength. He fights with blunt, double-handed objects such as wrenches, but more so knives and kunai.  

He cares deeply about Saki Konishi and fell into depression after her death. Much of his character development stems from his feelings for Saki and dealing with the hurtful possibility that Saki probably never felt the same way about him.