Heidi Augesvarer attends Musashi Ariadust Academy and works as an accounting assistant for student council treasurer Shirojiro Bertoni. She partners with Shirojiro both professionally and personally, sharing his focus on frugality and profitability despite her ever-present smile and uplifting, optimistic personality. Her constant cheerfulness defines her demeanor.

She possesses light blonde hair reaching her hips, blue eyes, and is often illustrated with distinctive cheek curls. Heidi typically wears light-colored clothing, sometimes featuring an armband. A white, fox-like Maus named Erimaki constantly accompanies her as her companion.

Within the academy, Heidi interacts with classmates such as Toori Aoi, Kimi Aoi, Masazumi Honda, Futayo Honda, and Nate Mitotsudaira. Her primary role involves supporting financial operations alongside Shirojiro, reflecting their mutual commitment to thrift.