Nils John Mifune is one of the five legendary heroes known as the Five Knights who fought in the Golem War fifteen years before the events of the series, a conflict that ultimately led to the defeat of the dark wizard Dark Schneider. He is a Samurai High Master and a peerless practitioner of the Kyokushin Itto style of swordsmanship. Following the war, he became the seneschal, or elder, of the former Kingdom of Iron Maiden, also known as Aian Meide. In the Hell's Requiem arc, he serves as the master of a group of highly trained samurai who oppose the forces of Kall-Su and the Sorcerer Shogun. Physically, Mifune is an older man with long black hair, a lengthy beard, and a black outfit with fingerless gloves. His personality is calm, serious, and reserved; he is quiet and does not share much about his personal life, but he is known for his strong sense of justice and principled nature. He was drawn to the cause of Prince Lars, which led him to join the other heroes in the Golem War. His motivations are rooted in loyalty, duty, and a desire to protect the realm from chaos. He is deeply respected by his peers and students, one of whom is Joshua, who trained under him as a disciple. Over the course of the story, Mifune remains a steadfast and reliable figure, demonstrating strategic thinking and unwavering composure even in dire circumstances. His notable abilities lie in his mastery of the Kyokushin Itto sword style, placing him among the most formidable swordsmen in the setting, and his expertise as a samurai commander. He does not possess magical abilities but relies on his exceptional martial skill and leadership.