Mitsuru Kobayashi, the academically driven older brother of Makoto Kobayashi, balances sharp intelligence with a disciplined focus on university entrance exams. His relationship with Makoto remains marked by emotional distance and sparse communication, mirroring broader familial tensions. Pragmatic in managing family obligations, Mitsuru postpones his college aspirations to redirect financial resources toward Makoto’s education—a sacrifice met with resistance when Makoto chooses a public school over the proposed private institution. Mitsuru’s frustration over this decision masks a deeper concern for his brother’s future, sparking heated confrontations that expose their fractured dynamic.

Though outwardly detached, Mitsuru intermittently reveals protective instincts. After delinquents assault Makoto, he retrieves his injured brother and silently ensures his safety. He later challenges Makoto’s dismissive attitude toward their mother, noting her shift from prepackaged meals to homemade cooking as evidence of her attempts to mend family bonds—a detail underscoring Mitsuru’s quiet vigilance toward household changes.

His narrative arc revolves around conflicting priorities: academic rigor, dutiful sacrifices, and the struggle to bridge emotional divides within the family. Actions and choices remain tightly interwoven with these themes, reflecting unresolved tensions between personal ambitions and relational responsibilities.