Kan Ki, also known as Huan Yi, is a prominent and notorious character known as "The Beheader." Before his military career, he was the leader of the largest bandit gang operating in southern Qin. His background is rooted in trauma and marginalization; he was discovered near death as a child by the Saki Clan, a group of outcast youths who became his adoptive family. It was within this environment that he first encountered profound cruelty, culminating in the torture and death of his lover, Shio, at the hands of a local lord. This event forged a deep, unyielding rage within him against the world's injustices and the societal structures that enable them. In retaliation, he slaughtered the lord's entire household, an act that solidified his fearsome reputation.

After years of evading and defeating Qin forces sent to eliminate him, Kan Ki was recruited by the elderly Great General Mou Gou. Despite his mercenary nature, he served with unexpected loyalty as a vice general in Mou Gou's army. Following Mou Gou's death, Kan Ki's unparalleled strategic brilliance and his role in major campaigns led to his promotion, eventually earning him a position as the fifth member of Qin's new generation of the Six Great Generals.

Kan Ki's personality is defined by a chilling and charismatic cruelty. He is almost always seen with an arrogant smirk, possessing a crude sense of humor and sarcasm. He rarely displays panic or genuine distress, maintaining a cool and fearless demeanor even in life-threatening situations. However, this exterior masks a profoundly brutal and sadistic nature. He has no qualms about massacring surrendered soldiers or civilians, viewing such acts as a legitimate method of warfare. He delights in psychologically tormenting his foes, exemplified by his tactic of sending the mutilated corpses of tortured enemy soldiers back to their commanders to shatter morale.

His motivations are far more complex than simple bloodlust. While he claims to fight for the thrill of sanctioned warfare, those closest to him understand that he is driven by a pure, molten rage against the world's system. He views kingdoms like Qin as "cesspools" where the elite oppress the common people at will, and he has expressed indifference to the state's survival. Despite this nihilistic worldview, Kan Ki possesses a powerful, charismatic magnetism for other outcasts. He treats his inner circle of commanders—including Rai Do, Koku'Ou, and Ma Ron—as family. The Saki Clan, in particular, is regarded as his only true home and sanctuary. His actions are often motivated by a desire for retribution against those who harm his people, and he has shown rare moments of respect, such as when he honored the dying General Chou Tou or paid tribute to his former benefactor, Mou Gou.

Throughout the story, Kan Ki plays a pivotal role as Qin's most feared and unconventional weapon. His tactics are unorthodox, relying on psychological warfare, deception, and high-risk gambles rather than traditional military strategy. He excels at exploiting the emotional weaknesses of his opponents, a skill he demonstrated masterfully during the Koku You Campaign by terrorizing the enemy commander's homeland. His actions directly challenge the idealistic unification goals of Qin's King, Ei Sei, who condemned Kan Ki's greatest atrocity: the execution of one hundred thousand surrendered Zhao soldiers. This act, carried out as revenge for the death of his close commander Rai Do, ultimately highlights his fatal flaw—his deep-seated rage can override cold rationality.

Kan Ki met his end at the Battle of Hika during the northern Zhao campaign. Outmaneuvered by the Zhao genius Ri Boku, who exploited his reckless nature, Kan Ki and his core commanders were surrounded and annihilated. In his final moments, he launched a desperate, one-man assault that nearly killed Ri Boku himself, fighting relentlessly until he was overwhelmed by multiple spear wounds. His death marked the end of one of Qin's most brilliant yet ethically devastating military careers.