Isamu Uchiumi is the main protagonist of Jealousy's Book. He is also the younger brother of Senzai Uchiumi. Young isamu wears a red and white varsity jacket with black pants and hair. Isamu is a playful, and a sassy person who often loves to tease anyone, but still with a caring nature. I don't know how old is he but he's probably be like 15 there. And he's involved in sports at some point, as evidenced by his red varsity jacket, his slightly boastful personality, and his overall stamina