Katsutoshi Murase is a Japanese manga artist born on August 7, 1979, in Kanagawa Prefecture, Japan. He began his professional career after working as an assistant to manga creator Shinya Suzuki. Murase made his debut with the one-shot Fukuwajutsu, which won both an honorable mention and the Twelve Masters Prize in the Twelve Masters Newcomer Manga Awards in 2003, leading to its publication in Aomaru Jump in 2004.

Murase has worked on a number of original manga series as both a writer and an artist. In the late 2000s, he created the series K.O. Sen, which he both wrote and illustrated. This was followed by Dois Sol in 2011. From 2013 to 2014, he was the author and artist for Mongrel, a story about a young man who turns to kickboxing after struggling with feelings of inferiority toward his more athletically gifted younger brother.

Murase is best known for his role as the illustrator of the horror manga series Karada Sagashi. The series, based on a cell phone novel by Welzard, was serialized on Shueisha's Shonen Jump+ platform from September 2014 to December 2017. Murase's artwork helped the series become the first on Shonen Jump+ to surpass 100 million views. He returned as the illustrator for subsequent entries in the franchise, including the spin-off sequel Karada Sagashi Kai (2018-2019) and the manga adaptation of the live-action film, Karada Sagashi I (2022-2023). A new manga in the series, Re/Member The Last Night, began serialization in 2025 with Murase again providing the illustrations.

Following the success of Karada Sagashi, Murase continued to work primarily as an illustrator on other horror and thriller manga projects. He illustrated Arata Primal: The New Primitive in 2019 and Red List: Zetsumetsu Shinkaron from 2021 to 2022. In 2020, he illustrated Jisatsu Hōjo, a manga adaptation of the horror novel of the same name by Yoshihito Okita.

The popularity of Karada Sagashi led to multiple adaptations. An original net animation produced by Production I.G was released in 2017. A live-action film adaptation premiered in Japan in October 2022, followed by a sequel film, Karada Sagashi The Last Night, released in September 2025. These adaptations significantly raised Murase's profile as a creator whose work translates well to other media. Murase's artistic identity is closely associated with the horror genre, where his detailed illustrations effectively build suspense and depict unsettling scenarios. While his early original works like Mongrel and K.O. Sen explored sports and action, his career has become defined by his powerful visual storytelling in the horror and thriller genres.