Yoshiyuki Nishi is a Japanese manga artist best known as the creator of the series Muhyo & Roji's Bureau of Supernatural Investigation. The series, which he wrote and illustrated, was serialized in Shueisha's influential Weekly Shōnen Jump magazine from November 2004 to March 2008. Its chapters were compiled into 18 tankōbon volumes. Nishi later returned to the property with a sequel series, Muhyo & Roji's Bureau of Supernatural Investigation: Magical Genus Magic Tool Master Chapter, which ran on Shueisha's Shōnen Jump+ platform from March 2018 to March 2019 and was collected in two volumes.

The original Muhyo & Roji manga received an anime television adaptation produced by Studio Deen. The first season aired from August to October 2018, followed by a second season that ran from July to September 2020. For the anime, Nishi is credited as the original creator and also as the original character designer, indicating his direct involvement in the visual foundation of the adaptation. The work has been published in English in North America by Viz Media under its Shonen Jump imprint, with the 18 volumes released between 2007 and 2010.

Beyond this flagship series, Nishi has been credited with several other manga works and has provided art for a light novel, though these have not achieved the same level of international recognition as Muhyo & Roji. He was also an assistant to the renowned manga artist Takeshi Obata, known for works such as Death Note and Hikaru no Go, a connection that places him within a significant lineage in the manga industry. His body of work establishes him as a creator whose primary contribution is the original conceptualization, writing, and illustration of supernatural-themed shōnen manga.