及川 譲

My first friend is a reliable loner with a sense of justice.

A male classmate of Kazuhiro's in class 5 of the 2nd grade. On the opening day of the new semester, he and Kazuhiro had an unlucky collision on their way to school. He and Kazuhiro had an unfortunate collision on the first day of the new school year, which led to their friendship. He has excellent grades and high athletic ability, but does not participate in club activities. He is a loner in his class. For unknown reasons, he does not get along with his parents, which seems to have cast a shadow over Oikawa's personality. He has known Naho Kosuge since they were in the second year of junior high school. They have maintained a mysterious relationship, neither close nor estranged. While Oikawa looks at Naho with his characteristic wary gaze, he may envy the existence of Naho, who "lives alone" without depending on anyone.