Rin Bu Kun commanded the Rin Bu Kun Army as a general in Chu. His imposing physique featured a distinctive crab-like hairstyle with spiky sides and back hair, partial baldness, and a small beard, complemented by armor signifying his high rank. Generally easy-going, he permitted subordinates like Kou Yoku to taunt enemies despite potential risks. Confidence defined his combat philosophy, believing he grew stronger by defeating powerful foes, though encountering Tou triggered visible fear, causing his hands to shake. His extensive military career involved brutal campaigns against the Baiyue tribes along Chu's southern frontier. Operating where strength dictated survival, he consistently fought on the front lines, accumulating a personal kill count exceeding one hundred warriors long before becoming a general. He first appeared stationed at the Qin-Chu border, discussing recent events like Riboku's Yan campaign and Rin Ko's death with commanders Kou Yoku and Haku Rei. Later, he escorted Chu Prime Minister Shun Shin Kun to a secret meeting with Riboku, deducing talks of a Chu-Zhao alliance. Leading the Chu vanguard during the Coalition Invasion, his forces devastated Fort Nanko while bypassing other cities to advance north. Encountering Tou's 5,000-man Qin army, Rin Bu Kun demonstrated his combat prowess by instantly killing Qin commander Dou Kin with a single mace blow. At the Battle of Kankoku Pass, his army engaged Tou's forces directly. After easily defeating Roku O Mi in a duel, he faced Tou. Despite putting up strong resistance and adapting his mace techniques to counter Tou's Rasen swordsmanship, Rin Bu Kun was ultimately decapitated. His capabilities included immense physical strength (rated 93), leadership (85), and tactical knowledge (85). He wielded a mace with high proficiency, enabling swift stance changes and powerful strikes, and led charges from the front. Remnants of his army were absorbed into the Ka Rin Army after his death. He was married to Haku Sui, the older sister of his subordinate Haku Rei, placing him in his mid-to-late thirties at the time of his death.