Zenji Marui is a second-year student at Tōtsuki Culinary Academy living in the Polar Star Dormitory. He has short black hair, black eyes, and poor eyesight necessitating glasses, which define his appearance. His notably low physical stamina frequently leaves him exhausted or decrepit after exertion, sometimes requiring a cane. Despite lacking natural cooking talent and physical prowess, Zenji possesses exceptional academic gifts and deep food knowledge, earning him the nicknames "The Professor of Taste" and "The Walking Flavor Dictionary." This intellectual strength forms the foundation of his culinary approach. His personality blends studiousness with loyalty. Initially resenting Polar Star residents using his large room for gatherings due to his preference for studying, he eventually participates and forms close bonds, particularly with Shun Ibusaki. He cares deeply for his friends and supports them during challenges. Zenji's "literary cooking" style relies on applying theoretical knowledge from extensive research, analyzing gourmet techniques and ingredients to create dishes grounded in culinary literature and philosophy, rather than instinct or physical skill. Key involvements include surviving the grueling Tōtsuki Friendship and Rapport Training Camp, persevering through tasks like preparing 50 meals despite his low stamina. Selected for the Autumn Elections Preliminaries, his "White Potage Curry Udon" featuring a smooth vichyssoise-inspired roux impressed judges, earning 88 points and temporary second place in Block A; he ultimately tied for fourth and did not advance. He later supported peers during the Regiment de Cuisine against Central and the BLUE tournament. His development shows a shift from self-doubt to embracing his academic strengths within team efforts, becoming a more active participant in communal endeavors while maintaining his role as Polar Star's knowledge anchor.