Shizuya Wazarai is a Japanese manga artist best known as the creator of the historical fighting series Cestvs: The Roman Fighter. Born on December 31, 1969, Wazarai made his professional debut in 1995 with the serialization of Blaster Knuckle in the pages of Hakusensha's Young Animal magazine. That early work, which ran until 1996 and was collected in three volumes, presents an alternate history of 1880s America where the Ku Klux Klan are revealed to be flesh-eating demons, and follows a man named Victor Freeman who hunts them using a modified gauntlet called the Blaster Knuckle.

Wazarai is noted to have been a high school friend of the renowned manga creator Kentaro Miura, author of Berserk, as well as fellow manga artist Koji Mori. He later worked as an assistant to Miura, and commentators have observed that Miura's detailed artistic style and thematic approach had a significant influence on Wazarai's own work. Wazarai's art style, particularly in Blaster Knuckle, has been described as similar to the early volumes of Berserk.

Wazarai achieved his greatest success with Cestvs: The Roman Fighter, a manga series written and illustrated by him. The first series, titled Kentō Ankoku Den Cestvs, was serialized in Young Animal from November 28, 1997, to March 13, 2009, and was later collected in fifteen tankōbon volumes. The story follows Cestus, a young slave boy in ancient Rome who fights as a bare-knuckle gladiator to win his freedom, training under a legendary fighter. A sequel series, Kendo Shitō Den Cestvs, began serialization in Young Animal on May 28, 2010, and has continued publication across multiple platforms, including Young Animal Arashi, the Manga Park web platform, and Young Animal Zero. As of 2023, eleven volumes of the sequel have been released.

An anime television adaptation of Cestvs: The Roman Fighter aired on Fuji TV's +Ultra programming block from April to June 2021, consisting of eleven episodes. For this production, Wazarai is credited as the original creator. The anime was directed by Toshifumi Kawase and produced by Bandai Namco Pictures for 2D animation and Logi Magi for 3D animation.

Wazarai's body of work is characterized by a focus on intense, often violent physical combat set against historical backdrops. Both Blaster Knuckle and the Cestvs series are seinen manga, aimed at an adult male audience, and feature themes of struggle, survival, and the pursuit of freedom against oppressive systems. The Cestvs series in particular is noted for its depiction of Roman-era gladiatorial combat with a focus on bare-knuckle boxing, known as cestus. Through his long-running Cestvs franchise, which has spanned from the late 1990s to the present day, Shizuya Wazarai has established himself as a distinctive voice in historical action manga.