Masamune is a supporting character in the anime Samurai 7. He is a veteran of the Great War and works as a mechanic, most notably maintaining Kikuchiyo’s mechanical exoskeleton and repairing his body whenever it is damaged in battle. His background as a war veteran gives him practical knowledge of machinery and combat, but he prefers to operate behind the scenes rather than on the front lines. Masamune is pragmatic and cautious, yet willing to assist those he trusts. He initially helps Kikuchiyo and later extends aid to the other samurai who come to Kogakyo. When the samurai group needs to hide and escape from the city, Masamune offers his home as a safe haven and participates in a ruse—allowing himself to be tied up and roughened by Kikuchiyo to maintain their cover. Over the course of the story, he forms a friendship with Kambei and the other samurai, acting as a reliable ally. His key relationships are with Kikuchiyo, whom he serves as a dedicated mechanic, and with the rest of the samurai, who come to respect his resourcefulness. Masamune’s motivations stem from a sense of loyalty and a desire to help those fighting against oppression, though he does not seek personal glory. His notable abilities lie in his mechanical expertise, which allows him to repair advanced weaponry and keep Kikuchiyo operational. He does not undergo significant personal development; his role remains that of a steady, behind-the-scenes supporter.