Sōtarō Shinozaki, a 27-year-old information processing instructor for first-year students at Suginami Second High School, originates from the former Detention Center G Area. He possesses a unique ability called visual rights, which later becomes critical for the team's exploration missions. Standing 182.5 cm tall and weighing 72 kg, Shinozaki holds a black belt in karate, granting him substantial combat proficiency that heightens his effectiveness in close-quarters engagements.

Initially prioritizing self-preservation in the deadly game, he strategically manipulates others to ensure his own safety. This approach shifts decisively after a pivotal encounter with fellow participant Ryōhei Sudō, whose words catalyze Shinozaki’s transformation into a dependable and integral group member.

A defining past relationship involves Hayato Sōma, whom Shinozaki rescued from a fire during their high school years. This act forged a profound bond and earned him Sōma’s deep respect.

As the narrative progresses into its second and third phases, Shinozaki’s visual rights ability gains prominence, proving instrumental in advancing the team’s exploratory objectives. His role evolves to encompass tactical planning and frontline combat, solidifying his position as a key asset within the group dynamic.