The captain and setter of the Aoba Jousai High School Volleyball Club. He is a very talented setter and volleyball player with a bad personality. Oikawa also frequently makes cheerful remarks, but follows them up with serious or intimidating afterthoughts. Despite his flirtatious and blasé exterior, Oikawa is extremely intelligent and cunning, to the point of his own teammates stating they wouldn’t be friends with him, but they are.