Mint Rondo is a female Tonttu, a species from Nordic folklore linked to winter solstice and Christmas traditions. She sports distinctive mint-green hair, usually in a ponytail. Within Santa Company—the organization managing global gift preparation and delivery—she works in the Gift Department, assisting with wrapping and preparing children's presents while contributing to worldwide product sales.

Gentle in nature, Mint Rondo deeply admires her skilled older brother. Driven by his example, she undertakes a specialized island training program, marking a pivotal commitment to her professional growth at Santa Company.