Hideo Sotomura, a student in Class 1-D at Advanced Nurturing High School, stands at average height with a slightly rounded build, sharp green eyes behind glasses, and spiky black hair. His wardrobe includes the standard first-year red tracksuit worn during the island exam and a brown trench coat donned while overseeing the Argos Team’s covert mission to surveil the girls’ changing area. Academically, he maintains middling grades: D in academic ability, C+ in intelligence, D in decision-making, E in physical skills, and C in cooperation. A self-proclaimed otaku, he immerses himself in bishoujo games, manga, and anime, peppering conversations with antiquated Japanese phrases. This linguistic habit drew sharp rebuke during the Mixed Training Camp, where a Zazen instructor mocked his speech as absurd, forcing him to adopt more conventional language. Socially inconspicuous, Hideo often fades into the background during pivotal class events. Yet he seizes pragmatic opportunities, exemplified by his analytical support for the Argos Team’s operations. Personality assessments label him an ISTJ and Enneagram 5w6, reflecting his methodical data-collection habits, preference for logic over emotion, and structured approach to tasks. In the cruise ship Special Test, he joined the Mars group alongside Kiyotaka Ayanokōji, Kei Karuizawa, and Teruhiko Yukimura, tasked with identifying a VIP. Though his role stayed peripheral to core strategies, his participation underscored his consistent, if understated, presence in collaborative efforts. Documented accounts highlight his school-centered activities and minor operational contributions, with interactions confined to academic or exam-related support roles.