One of the protagonists of Endou-kun no Kansatsu Nikki, Tsuda comes off as intimidating to others due to his tall height and cold facial features, but is very aloof and indifferent once spoken to. Although he's accepted his mundane life as uneventful and unchanging, Tsuda soon realizes that he can't stop looking at the boy who sits in front of him in class. Due to a friend's persistence in giving the guy a haircut, Tsuda grows closer to the quiet boy with the expressionless face and finds the change he needed in his life.