Kōichi Shindō stands 173 cm tall, born April 2, with spiky medium-length orange hair parted right and a prominent cowlick, complemented by lime-green eyes. He typically wears his Yasaka High uniform or casual outfits like a white polo shirt with black jeans. During junior high, Shindō attended school alongside Izumi Miyamura and Makio Tanihara. Popular and upbeat, he befriended Miyamura despite peers ostracizing him over piercings and a gloomy demeanor. Shindō defended Miyamura against critics like Tanihara, arguing his isolation stemmed from mistreatment. Fascinated by Miyamura, Shindō became his first and closest friend—a bond Miyamura credits for embracing his true self. Though initially forgetful with names, particularly struggling with Miyamura’s, their connection deepened through frequent home visits and family familiarity. Post-junior high, Shindō entered Yasaka High per parental academic expectations, while Miyamura enrolled at Katagiri High. At Yasaka, Shindō repeated his second year multiple times due to poor grades, once after smoking-related discipline. This fueled disapproval from girlfriend Chika Ichijou’s parents, who deemed him unsuitable. Unyielding, he vowed self-improvement and asked Chika to wait one year for his graduation. Their relationship ignited when Shindō confessed and she instantly accepted. He devoted 60% of his time to Chika, who remained indifferent to other girls’ attention. She influenced his habits—slapping cigarettes from his mouth and, with Miyamura, confronting his cheese aversion. Shindō allocated 30% of his time to Miyamura, engaging in playful antics like resting his foot on Miyamura’s head and teasing him about romantic interest Kyouko Hori. His friendship with Tanihara endured past conflicts, with Tanihara playing straight-man to Shindō’s humor and occasionally receiving his tutoring. Shindō blends cheerfulness with sporadic seriousness, expressing emotions openly—joking about Miyamura as his "first crush" or voicing hurt over Chika’s parents’ disdain. He visits friends impulsively, like appearing at Miyamura’s home at dawn, and supports them, urging Miyamura to pursue Hori. He detests cheese (a recurring joke), excels at Tetris, and refuses haircuts. He jokes about rivaling Miyamura’s piercings and historically smoked—a detail present in the original webcomic but omitted in the manga.