Yū Shimizu is a Japanese writer known for creating several light novel and manga series, primarily in the fantasy and isekai genres. Shimizu's career as an original creator is marked by a focus on worlds that blend high fantasy concepts with game-like mechanics, often drawing inspiration from tabletop role-playing games.

Shimizu is the author of the light novel series Bladedance of Elementalers, also known as Seirei Tsukai no Blade Dance. This series stands as one of Shimizu's significant early works in the fantasy genre. Another notable light novel series written by Shimizu is The Demon Sword Master of Excalibur Academy, or Seiken Gakuin no Mahou Tsukai. These works helped establish Shimizu as a creator within the fantasy light novel space.

In addition to light novels, Shimizu is the credited writer for the manga series Otherworldly Munchkin: Let's Speedrun the Dungeon with Only 1 HP!. The story follows Yukito Kirihara, a high school student who loves tabletop role-playing games, as he is reincarnated into another world after being killed by a monster. Armed with the knowledge of a TRPG player and with only one hit point, he embarks on a quest to find his younger sister, who was also reincarnated. The series began serialization in Kodansha's Suiyōbi no Sirius magazine and on the Nico Nico Seiga website in February 2019, with illustrations provided by Makoto Aogiri. As of November 2024, the manga has been compiled into eleven tankōbon volumes.

An anime television series adaptation of Otherworldly Munchkin was announced in November 2024. The adaptation is produced by the animation studio Durandal, marking its debut production, and is directed by Mamoru Yokota. The anime was initially scheduled to premiere in October 2025 but was subsequently delayed to improve the quality of the series.

A recurring element in Shimizu's work, particularly evident in Otherworldly Munchkin, is the incorporation of tabletop role-playing game mechanics and terminology. The title itself refers to a "munchkin," a type of player who exploits game rules to their advantage, and the story is framed around the concepts of character sheets, dice rolls, and strategic rule usage. Shimizu has stated that the series is infused with fond memories of playing tabletop role-playing games during their school years. This integration of TRPG elements constitutes a recognizable aspect of Shimizu's creative identity within the fantasy genre.