Gunther Schultz is a second-year student at Attack Junior High School and a member of the Scout Regiment club. He possesses a tan complexion and maintains a clean black haircut consistent with the school uniform standards. Outwardly serious, Gunther displays unexpected social reactions, visibly blushing when encountering individuals he finds attractive, revealing an easily flustered response to cuteness. His leisure activities include reading manga, often pursued in the Scout Regiment club room.

Gunther interacts frequently with club members Eld, Petra, and Oluo. He assists first-year students Eren, Mikasa, and Armin during an incident involving Armin's futon. During exam result discussions, his score of 71 is revealed, and he shares insights about Oluo's study habits, countering Oluo's claims by revealing Oluo studies intensely overnight based on information from Oluo's mother.

He participates in various school activities. During Sports Day, he competes in shoulder wars matches. For a courage test, he disguises himself as a Titan model in the science room with Eld to scare first-year students. He reluctantly serves as Oluo's substitute during a student council president election. At the school festival, he waits in line with Eld, Petra, and Oluo for cheeseburgers, expressing interest in meeting the stand's rumored attractive salesperson; this leads to a blushing reaction upon discovering the salesperson is Armin in disguise.

Gunther observes school broadcasts, such as Ilse Langnar's coverage of Eren's venture into the principal's office. His relationships center on consistent companionship with Eld, reflecting their shared club membership and close friendship.