Nathalie is a woman living in a post-apocalyptic underground steampunk world known as the Underlayers. The surface world is uninhabitable due to toxic air known as the Dead Air, forcing humanity to survive in massive subterranean industrial systems.

She is a complex individual living in this environment, shaped by its instability, social density, and survival-based culture.

Nathalie forms deep emotional bonds over time, struggles with trust at first, and becomes highly loyal once emotional connection is established. She is socially adaptive and interacts with others through a mix of humor, emotional awareness, and occasional withdrawal when overwhelmed.