Shō Adachi, a second-year middle school classmate of Kyōtarō Ichikawa and Anna Yamada before switching classes the following year, sports short brownish-blonde hair, an average build, and distinctive smaller irises. His brash, perverted demeanor drives frequent shallow discussions about sexual desires with friends Kanzaki Kenta and Ōta Chikara, often pulling classmates into inappropriate jokes. Yet beneath this crass exterior lies a staunch male honor and sporadic perceptiveness, evident when he notices Ichikawa’s deepening bond with Yamada or acknowledges Sekine Moeko’s inclusive Valentine’s Day chocolate gestures.

Initially fixated on Yamada, Adachi harbors lewd fantasies and vies for her attention through clumsy overtures. His rivalry with Ichikawa culminates in a sports festival cavalry battle, where a confrontation over superficial intentions forces Adachi to yield. This sparks a genuine friendship, marked by his gradual inclusion of Ichikawa in casual hangouts and group dynamics, signaling mutual respect.

Strained relations with his mother stem from his academic struggles and behavior, though her interventions—like compelling him to thank Sekine—hint at underlying care. Despite his social initiative, female classmates routinely deflect his advances. As a judo club member, he shares athletic engagements with Ōta.

Adachi’s growth surfaces in moments of self-reflection: recognizing Yamada’s integrity during a past festival mishap or conceding the emptiness of his initial pursuit. Though his antics sometimes overstep—hoarding a tissue from Yamada’s nosebleed or probing awkward questions on trips—they mirror typical adolescent immaturity. Evolving from comic relief to a loyal ally, his arc underscores themes of maturation and camaraderie.