Kozue Matsumoto, a high school student and daughter of landlady Kinuyo Matsumoto, carries the legacy of her father Taizan, whose death in the Underground Arena shaped her disdain for violence. Initially immersed in ordinary routines—caring for Baki Hanma’s dog, voicing concern over his school absences—she maintained a quiet yet perceptive demeanor, masking deep affection for him while grounding his chaotic life with meals and reminders to prioritize balance. Her bond with Baki transitioned from friendship to romance after witnessing his determination in the Underground Arena, crystallizing during a visit to Emi Akezawa’s grave. This awakening led her to attend his matches, offering unwavering emotional support. At the Maximum Tournament, their relationship deepened: Baki openly declared his care, they shared their first kiss, and later became physically intimate before his pivotal clash with Ryuukou Yanagi, a milestone in his maturation. Kozue’s quiet strength surfaced through defiance. She confronted Kaoru Hanayama for belittling her relationship, condemning the fighters’ disregard for women’s roles. She challenged Yuujirou Hanma during his violent clashes with Baki, demanding an end to their brutality. These acts bridged Baki’s martial world with everyday humanity, emphasizing empathy over aggression. External trials emerged, including advances from Muhammad Ali Jr., whose kindness she acknowledged but rejected, deeming him emotionally immature. Baki’s decisive victory over Ali Jr. reinforced her loyalty, anchoring her choice to stand by him. Physically, Kozue is marked by brown hair and eyes, often tied in braids or a ponytail, her 160 cm frame clad in school uniforms or casual attire. Her design subtly shifted across adaptations, adjusting hairstyles and clothing while retaining her relatable essence. Though her prominence waned in later arcs, Kozue proved indispensable during Baki’s poisoning recovery, accompanying him to China and aiding his healing. Yuujirou himself recognized her impact, crediting her with fortifying Baki’s emotional core. Even as narratives prioritize combat, Kozue endures as his stabilizing force—a testament to love’s resilience within a world ruled by strength.