Gakushyu is a student at Nanyo Academy and holds the rank of a B-ranked fighter. He is recognized as one of the four strongest students at his school, a group known as the Big Four, although he is consistently depicted as the weakest member of this elite circle. Physically, he is an imposing figure, characterized by a large, muscular build and spiky black hair, typically seen wearing his school uniform.

His personality is presented with some conflicting traits depending on the source. One description portrays him as a man of honor with a very nice personality, priding himself on his integrity and muscular physique, while also being pessimistic about his side's chances in conflicts. In contrast, another account suggests he is somewhat sadistic, enjoys fighting, and often carries an uncaring attitude toward most situations. Despite his formidable size and dedication to training, his actual combat skill is notably poor compared to other top-tier fighters like Shimei Ryomou or Ryofu Housen, and he frequently loses to stronger opponents.

Gakushyu's role in the story is primarily that of a supporting character within Nanyo Academy. He serves as a sort of de facto commander or investigator during times when the school's leadership goes silent or behaves oddly. For example, he was the first to discover and investigate the strange behavior of a leader named Enjutsu. His motivations often revolve around his duty to his school and his position, showing concern for its leadership decisions and the fate of its fighters. He once confronted another student, Kouha Kannei, to inform him that an imperial order had been withdrawn, demonstrating his willingness to intervene in the affairs of his powerful peers.

His key relationships are with the other members of the Big Four and the protagonist, Hakufu Sonsaku. He has a rivalry and shares a history of conflict with Shimei Ryomou, who easily defeated him in battle. He is shown interacting with and expressing concern about characters like Genpou Saji and Enjutsu. Hakufu gives him the nickname Gaku-chan, indicating a level of familiarity despite their initial hostile encounter where he effortlessly threw her into a building with one finger, only to later be affected by her power in a mysterious way.

Over the course of the series, Gakushyu's character shows some development, particularly in the anime adaptation where he plays a slightly more important role than in the original manga. In one anime series, he becomes significantly tougher and is able to fight on even terms with an opponent like Kakouen, a marked improvement from his earlier showings. His development also extends to his personal life post-conflict, as he is shown getting a job in a store, though his aggressive nature remains as he risks being fired for throwing a troublesome customer through a window.

His notable abilities include the use of chi blasts, a technique he learned after being blasted through a wall by Ryomou. However, even his chi attacks are not exceptionally powerful, as demonstrated when he blasted an opponent who was still able to get back up afterwards. His primary assets remain his raw physical strength and large, muscular frame, though his lack of refined technique often leaves him vulnerable in fights against truly skilled martial artists.