Saruno's best friend and adviser. Their friendship is questionable sometimes, though, as they make fun, yell at and fight each other often. Sawamatsu helps Saruno train for the entrance exam to the baseball club.
Kengo is a very supportive friend who stands by Saruno's side even when he knows his friend's antics will get them into trouble and even helps him train for the baseball club's entrance exam. Saruno counts on Kengo for advice.