Called "Gaku-chan" by Saji, he is a third-year student at Nanyo Academy, a B-ranked fighter, and one of the Big Four. A large, muscular man with a scary face but a very nice personality, he is man of honor to the very core, and prides himself in this and in his rippling muscles, but usually gets beaten by all but the weakest of opponents. He learned how to use chi blasts after Ryomou blasted him through a wall without even twitching. Despite his strength and training, his skill is far poorer than that of Ryomou and Ryofu's, as shown when he blasted Myosai who still got up afterwards. Though he is helping Nanyo with their alliance with Seito, he is pessimistic about their chances, such as when he commented the plan of bodily harm couldn't work since Kogai had been killed earlier. He later assists along with Saji and Rikuson to test Hakufu's worth as leader of Nanyo, and has no serious involvement since then.
Gakushu plays a slightly more important role in the anime than in the manga, serving as a sort of de facto commander when Enjutsu and Saji go silent. He even investigates Enjutsu's odd behavior, and is the first to find out he is dead but is captured by Kannei. He gets beaten even more than in the manga, only to miraculously recover an episode later. He is also shown to have a sweet tooth, and even holds a meeting with Koukin in an ice cream shop. In Dragon Destiny, he becomes a lot tougher and was able to have an even fight with Myosai. At the end of the series he gets a job in a store, but risks getting fired for throwing a customer through a window when he would not stop harassing a woman.