Kisaragi Midori serves as Toshio Ōtomo's best friend while nurturing an unrequited affection for Yū Morisawa. His shy, bashful nature compels him to depend on Toshio’s aid for romantic gestures toward Yū, whether confessing feelings or arranging interactions. Midori reacts fiercely to any disrespect toward Yū, displaying intense protectiveness and visible anger—especially when Toshio belittles or insults her.

Overweight and often the source of comic relief, Midori embodies the bumbling sidekick role to Toshio. He endures frequent slapstick mishaps, contrasting his physical stature with a gentle, meek demeanor as a kind-hearted giant. His consuming passions center on devouring copious amounts of food and his unwavering admiration for Yū. Academically challenged with poor grades, he reinforces his well-meaning but unfocused persona.

Within their friendship, Midori tolerates Toshio’s occasional rudeness—including dismissive remarks about his academic struggles or appearance—yet remains steadfastly loyal. He regularly appears in group settings involving Yū and Toshio, anchoring his narrative purpose in comedic misadventures and his persistent, unsuccessful courtship of Yū.