Masao Oba is a 17-year-old Japanese male with black hair. He endured bullying by stronger individuals until witnessing Mao Lan defeat a group of bullies. This event inspired him to seek training under her mentorship. Becoming Mao Lan's dedicated student, he learned fundamental techniques from her family's martial arts style. Through disciplined effort and respect for his elder instructor, Masao developed basic self-defense capabilities sufficient to protect himself against ordinary fighters.

His journey traces a clear evolution: from an inexperienced individual lacking combat skills to someone capable of practically applying learned techniques. This progression focuses on foundational martial arts proficiency, not advanced mastery. The narrative maintains his role within training contexts and personal growth centered on self-defense; it does not depict him participating in professional fighting tournaments like Prime Mat. His character arc emphasizes overcoming vulnerability through consistent, incremental skill acquisition under guidance.