Inagaki Kouji is a student at Jougaoka High School. He excels at sports and is constantly sought after by numerous clubs but he refuses to join any of them, instead devoting his time to chasing after Arisawa Atsushi, who he was childhood friends with. When they were younger Kouji always protected Atsushi and they resolved to get married, giving each other their first kiss. Kouji moved away from Atsushi when he was still young, and is delighted to find out Atsushi is now in the same high school as him.
He was born in Osaka and lives with his mother. He has an older sister, Akiko, who moved out and has two children of her own. He has a very loud and blunt personality and constantly forces himself on Atsushi.