Retsu Kaioh, born Eishuu Retsu, honed his skills at Heilongjiang's Bailin Temple under the name Shaoron Retsu. His early devotion to Chinese Kenpo demanded extreme physical and mental discipline, exemplified by carving perfect stone spheres barehanded. Despite his prowess, authorities barred him from the elite Kaiou title examination. He escaped confinement by defeating six armed guards and challenged his master, Kaiou Ryuu, who dismissed his abilities. This rejection fueled relentless training, ultimately earning him the Kaiou title. A sparring accident during this period resulted in a partner's death, though its connection to his later confinement remains ambiguous. During the Maximum Tournament, Retsu served as both antagonist and competitor. He confronted Katsumi Orochi over karate's perceived inferiority to Chinese Kenpo, igniting a rivalry. His tournament matches featured a swift Spinning Lotus victory against Sergei Taktarov, a tactical win exploiting wrestler Mount Toba's knee weakness, and a dominant one-punch Sunkei knockout of Katsumi Orochi. His semi-final bout against Baki Hanma ended in defeat after Baki anticipated his strategies. These fights revealed Retsu's impatience and overconfidence, traits contributing to his eventual downfall. Post-tournament, Retsu evolved from rigid traditionalist to open-minded martial artist. He forged a friendship with Katsumi Orochi, training at the Shinshinkai Dojo to learn diverse styles while teaching Chinese Kenpo. This period showcased his growing compassion, particularly his pity for the mentally disabled Kaiou Dorian. Yet, his combat impulsiveness persisted, culminating in a brutal clash against the prehistoric Pickle that cost him his leg, leading to permanent use of a pegleg. This disability scarcely hindered his daily life or combat effectiveness. In later arcs, Retsu dueled the resurrected samurai Musashi Miyamoto. Musashi breached Retsu's defensive Xiaoli technique—a hyposthenia state absorbing impacts—by exploiting spinal tension, severing organs and his spine, causing Retsu's death. His final act gifted his prosthetic leg to Musashi as a symbol of respect. The non-canonical spin-off *Baki Gaiden: Retsu Kaioh wa Isekai Tensei Shitemo Ikkou ni Kamawan* depicts Retsu reincarnated in a fantasy world after his *Baki-Dou* demise, engaging new adversaries while retaining his martial prowess and identity. Physically, Retsu stood 176 cm (5'9") and weighed 106 kg (233 lbs), characterized by a muscular build, long black hair in a pigtail braid, and thick eyebrows. He typically fought shirtless, wearing dark blue or black monk pants and boots, with his pegleg becoming a permanent fixture after the Pickle battle. His fighting style centered on Chinese Kenpo, incorporating techniques like the neck-breaking Spinning Lotus throw, the zero-distance power strike Musunkei, the eye-targeting Invisible Blinding compressed air attack, and the momentum-amplifying Crushing Fist punch. He pragmatically employed tactics like hair-pulling, projectile dirt, and alcohol-based fire attacks. Retsu possessed sharp analytical prowess, rapidly dissecting opponents' techniques and weaknesses, a skill noted by Musashi Miyamoto.