Yū Yanase, a freelance mangaka assistant, sports medium-length brown hair and light maroon eyes, habitually wearing glasses during work sessions. His signature light brown duster jacket becomes a staple during collaborations. Childhood friends with Chiaki Yoshino since junior high, their bond formed over shared literary passions, though Yanase’s admiration for Yoshino’s "perfect" hands evolved into unrequited romantic longing. Playfully provoking jealousy in rival Yoshiyuki Hatori, he navigates unresolved affections while channeling professional dedication to remain near Yoshino, eventually assisting revered manga artist Ijuuin Kyo—a figure he idolized since youth.

Collaboration with Ijuuin deepens as mutual vulnerability surfaces: Yanase confesses past romantic rejection, prompting Ijuuin to bridge their shared loneliness through hesitant yet growing intimacy. Their relationship blossoms into a partnership, shifting Yanase’s focus from Yoshino to reciprocal affection. Tensions with Hatori persist, oscillating between rivalry and reluctant professional respect, though a fraught attempt to overstep Yoshino’s boundaries leads to rejection, cementing Yanase’s emotional pivot toward Ijuuin.

Cheerful yet mischievous, Yanase masks private insecurities behind teasing antics, particularly toward Hatori. His aversion to sweetness and pretense contrasts a sexually sensitive nature and professional reliability—traits earning Ijuuin’s trust, symbolized by entrusted residence keys. Evolving from secondary rival to protagonist in spin-offs exploring his "Junjou Sentiment" arc with Ijuuin, Yanase’s journey traces resilience, navigating societal expectations and mutual growth. Even as he occasionally tests lingering boundaries with Yoshino, his narrative culminates in emotional maturity, balancing friendship, love, and self-discovery.