Mitsuo Yanagisawa is a freshman studying law at a private university in Tokyo. He comes from a wealthy family and grew up as the childhood friend of Kouko Kaga, who developed a long-standing romantic obsession with him. Hoping to escape her overwhelming pursuit, Mitsuo secretly took the entrance exam for a different university, but Kouko discovered his plan and enrolled in the same school, continuing her pursuit. At university, he meets Banri Tada, and the two quickly become best friends. Mitsuo also develops a crush on Chinami Oka, though she ultimately rejects him, a turning point that leads him to cut his hair and dye it blond in an attempt to start fresh.

Mitsuo has a kind and generally mature nature, though he is easily distracted and initially finds Kouko’s personality irritating. Despite his frustration with her, he still cares about her well-being, as seen when he checks on her after a troubling incident. He is emotionally stable and often serves as a rational, grounded presence among his friends. His primary motivations are to establish his own identity separate from Kouko’s influence, and to find genuine romantic connection. Over the course of the story, Mitsuo grows more confident and learns to navigate rejection and friendship. He later develops feelings for Linda (Nana Hayashida), leading to a mutual romantic interest by the end of the series. His role in the story is that of Banri’s loyal confidant and a source of both drama and humor, contributing to the series’ exploration of love, identity, and independence. Mitsuo’s notable strengths lie in his emotional stability and his ability to act as a voice of reason, even while dealing with his own romantic missteps.