Mitsuya Takanashi is a popular high school student who exudes confidence and assertiveness, often masking his insecurities with a snobbish, arrogant demeanor. His conventionally attractive appearance—short blonde hair, brown eyes, and two piercings adorning his left ear—cements his status as an "ikemen." Romantic fixation on Iroha Igarashi fuels his rivalry with Hikari Tsutsui after she rejects him for Hikari, sparking intense jealousy.

Driven by possessiveness and a transactional view of relationships, Mitsuya devises a scheme to tarnish Hikari’s reputation, spreading false rumors branding him a lolicon. He manipulates his younger sister, Anzu, into staging an incident that falsely accuses Hikari of misconduct. Though the plot temporarily deepens Hikari’s social isolation, his existing ostracization as an otaku blunts its severity.

When Iroha and Anzu expose his deceit, Mitsuya confronts remorse and begins a gradual transformation. He apologizes to Hikari and his family, slowly integrating into Hikari’s circle with a newfound cooperative attitude. His dynamic with Arisa Ishino shifts from indifference to mutual attraction, marked by tsundere-like hesitance as he battles to voice his feelings.

Central to Mitsuya’s background is his devotion to family. Raised in a single-parent household, he dedicates himself to supporting his mother and sister, aspiring to secure their stability through university education. This earnest responsibility starkly contrasts his earlier antagonism, revealing a complex duality of self-interest and familial loyalty.

By the series’ end, Mitsuya reconciles with Hikari and commits to a relationship with Arisa, later marrying her and fathering a child. His journey from self-centered rival to mature, accountable figure underscores themes of redemption and the potential for growth within flawed individuals.