Apachai Hopachai, a Muay Thai master of Ryōzanpaku Dojo, emerges as a central figure shaped by a turbulent past. Born with extraordinary strength, he endured childhood trafficking to a crime syndicate, where he shattered a hurled cane and subdued the boss’s guards. Rescued by Agaard Jum Sai, he honed his skills at Romtyphoon Gym, dominating underground circuits with unstoppable force, often felling opponents in a single strike. Despite his lethal prowess, Apachai radiates childlike innocence and naivety. He harbors deep affection for children and animals, once adopting a tiger cub he mistook for a large cat. This gentleness clashes with combat reflexes forged in life-or-death struggles since youth, sometimes unleashing fatal force unintentionally. Struggling to moderate his strength due to survival instincts and language barriers, he unknowingly retains habits from darker days—interjecting “Apa” into speech and answering calls with phrases like “We have your child hostage,” echoes of his trafficker past. Apachai’s mastery spans Muay Thai and the lethal Muay Boran, which he practices covertly at night to shield disciple Kenichi Shirahama from its deadly techniques. His physical feats defy limits: leaping hundreds of meters, pulverizing stone statues, and surviving mortal wounds like a pierced torso through sheer will and allies’ aid. His resilience lets him battle on despite near-fatal injuries, even enduring a day without breath thanks to immense lung capacity. His path twisted after Agaard’s departure, leaving him starved and unwittingly serving traffickers. Discovering their crimes, he freed enslaved children and diverted stolen resources to a destitute village, cementing his ethics and loyalty to Ryōzanpaku under Hayato Fūrinji. With Kenichi, initial training mishaps from unchecked power evolved into empathetic restraint, treating his disciple as a cherished child. His growth shines in mundane triumphs like laundry, mastered through clandestine practice. Pivotal battles mark his legacy, including a duel with Agaard in the Okinawa Arc, where childhood bonds clashed with mutual respect. Mortally wounded, Apachai revived through sheer resolve, vanquished the Bantou Master, and endured urgent medical care. Later, he confronted Yami enforcers and bolstered Kenichi against rising threats, embodying both guardian and mentor. His vulnerabilities—a phobia of airplanes rooted in trauma and a gullibility once exploited by criminals—counterbalance his might. Apachai’s journey mirrors gradual maturation, melding deadly skill with a gentle heart, epitomized by friendships like Honoka Shirahama’s and his place in Ryōzanpaku’s communal life.