Yuzu Izumi attends Seki Tomo High School as a second-year student in Class 2, alongside Fumiya Tomozaki. She possesses medium brown hair, often styled with a mini bun on the right side, and brown eyes, featuring a distinctive mole gracing the left side below her mouth. Her overall look reflects a trendy, modern high school aesthetic with gyaru influences, balanced by a kind demeanor.

Socially integrated into Erika Konno's circle, she maintains friendships with classmates like Aoi Hinami and Minami Nanami. Empathy defines her personality, coupled with a strong aversion to conflict. This aversion leads her to reluctantly tolerate Erika Konno's unreasonable actions despite personal discomfort. Yuzu develops feelings for classmate Shuuji Nakamura after he becomes engrossed in the game Attack Families (AtaFami/TackFam). To connect with him and become his practice partner, she learns the game under Fumiya Tomozaki's guidance, initiating their friendship. Their relationship evolves to include mutual teasing, though they persist in using formal address.

Following the start of her relationship with Shuuji Nakamura, Yuzu takes up sewing, creating handmade gifts such as a tissue case for him. This act inadvertently fuels Erika Konno's anger, contributing to Erika's later isolation from the class. Demonstrating devotion, Yuzu studies intensely to achieve high test scores during Shuuji's school absence, aiming to support his return. Her commitment culminates in a rare act of defiance: standing up against Erika to defend both Shuuji and Fumiya, marking a departure from her typical conflict-avoidant nature.

Her personal hobbies include shopping and needlework. At school, she participates in the badminton club. Her name "Yuzu" combines "excellence, superiority, gentleness, tendency" (優) and "bell" (鈴), while her surname "Izumi" translates to "spring, fountain" (泉), reflecting aspects of her character.