Nagisa Fukunuki, also known as Nudiste, is a supporting character in the anime Loner Life in Another World. She is a high school student who, along with her entire class, is summoned to a fantasy world. Before the summoning, Nagisa was an elite swimmer who had reached the level of an Olympic candidate. She has short green hair, yellow eyes, and stands 165 centimeters tall. Her nickname Nudiste reflects her tendency to prefer minimal clothing or to express a desire to remove her uniform when feeling hot or uncomfortable.

Nagisa is part of the athletic girls' group among her classmates. After the class is transported to the other world, the students split into factions, and the athletic girls eventually join the protagonist Haruka in his dwelling. Nagisa's personality is not extensively detailed in available sources, but she is portrayed as an energetic and physically capable individual who finds the unfamiliar climate uncomfortable and longs for amenities like a bath. Her primary motivation is to adapt to the new world while maintaining her straightforward, active nature.

In the story, Nagisa has a supporting role. She interacts with Haruka and the other girls who seek his protection and assistance. Her key relationships are with her fellow classmates, especially the other athletic girls, and Haruka, who provides for the group. There is no known significant character development for Nagisa within the anime's narrative, as she remains a background figure among the larger ensemble. Her notable ability is her exceptional swimming skill, which she likely retains in the new world, giving her a physical advantage in aquatic environments. However, the series does not extensively showcase her combat or magical prowess.