Nanashi is the Japanese manga artist known for creating the series Don't Toy with Me, Miss Nagatoro, which was adapted into the anime Don't Toy with Me, Miss Nagatoro and its sequel, Don't Toy with Me, Miss Nagatoro 2nd Attack. The name Nanashi is a pen name; in Japanese, it means nameless, and the author also uses the numerical pseudonym 774, which can be read as a goroawase, or numeric wordplay, for the same term. Nanashi was born in 1983 on the island of Honshu, Japan.

Before achieving mainstream success, Nanashi was a prolific creator of doujinshi, or self-published works, under the circle name 774 House. These early works were often posted on the art community website Pixiv and covered a wide range of genres, including many with explicit adult themes. The original concept for Don't Toy with Me, Miss Nagatoro first appeared as a webcomic on Pixiv in 2011, before being formally serialized by Kodansha beginning in 2017. Following the series' rise in popularity, Nanashi removed most of the earlier adult-oriented content from public profiles.

Don't Toy with Me, Miss Nagatoro is a romantic comedy that follows the daily interactions between a timid, art-loving upperclassman known only as Senpai and his lively, teasing underclassman, Hayase Nagatoro. The series marked a significant shift in the artist's career, moving from niche, often darker doujinshi to a widely popular mainstream manga. In an interview, Nanashi stated that the series was not planned as a rom-com from the outset, but rather developed in that direction as a result of Nagatoro's personality. The author also noted that the characters were not based on real-life individuals but were imagined entirely from within.

Regarding the anime adaptations, Nanashi has expressed that the most rewarding aspect was seeing the characters, which had previously existed only in their imagination, come to life through animation and voice acting. The creator maintains a low public profile, and much of the personal information available, such as birth year and place, comes from older sources, as Nanashi continues to value anonymity. The pen names themselves, meaning nameless, reflect this preference for privacy. Despite the shift to a lighthearted romantic comedy, the creator's earlier, more provocative artistic identity remains a documented part of their background in the doujinshi community.