Keisuke Itagaki, born Hiroyuki Itagaki on April 4, 1957, in Kushiro, Japan, is a Japanese manga artist best known as the creator of the long-running martial arts series Baki the Grappler. His pen name is derived from a character in a manga by his instructor, Kazuo Koike. Before entering the manga industry, Itagaki served for five years in the 1st Airborne Brigade of the Japan Ground Self-Defense Force, an experience that has directly influenced his work, including a semi-autobiographical manga series about his time in the military. During his service, he practiced amateur boxing and competed in the National Sports Festival. He also holds a second-degree black belt in Shorinji Kempo, a discipline he has practiced since his teenage years. He is the father of Paru Itagaki, the creator of the acclaimed manga series Beastars.

Itagaki made his professional debut in 1989 with the manga Make-Upper. His breakthrough came in 1991 when he began serializing Grappler Baki in Akita Shoten's Weekly Shōnen Champion. This series, which follows the violent exploits of young martial artist Baki Hanma as he seeks to surpass his powerful and often antagonistic father, Yujiro Hanma, became the foundation for a multimedia franchise. The original Baki the Grappler manga ran until 1999 and has since been followed by a succession of direct sequel series, including Baki (1999-2005), Baki Hanma (2005-2012), Baki-Dou (2014-2018), and Baki Dou (2018-2023). The latest installment, Baki Rahen, began serialization in 2023. Combined sales of the Baki series have exceeded one hundred million copies, making it one of the best-selling manga series in history. Beyond the main narrative, Itagaki has also overseen or contributed to numerous spin-off manga. These include Baki Gaiden: Scarface, Baki Gaiden: Kizuzura, which was listed as an example, and Baki Gaiden: Gaia to Sikorsky, a comedic spin-off written by Itagaki and illustrated by Takaaki Hayashi that began serialization in 2022.

In addition to his own franchise, Itagaki is known for his work on Garouden, a long-running adaptation of Baku Yumemakura's novel series, which he illustrated from 1996 to 2010. He also collaborated on the spin-off series Garouden Boy.

The Baki franchise has seen multiple anime adaptations that have introduced the series to a global audience. The first anime series, titled Grappler Baki, was produced in 2001. More recently, Netflix has produced several original anime series, including Baki (2018), which adapts the second manga series, and Baki Hanma (2021), which adapts the third. Itagaki is credited as the original creator for these productions. The provided example, Baki Hanma vs. Kengan Ashura, is a crossover anime film released on Netflix in June 2024, pitting characters from Itagaki's Baki Hanma against those from Yabako Sandrovich and Daromeon's Kengan Ashura. Itagaki’s direct involvement with these animated projects is primarily as the source material author, and he is not known for voice acting work.

Itagaki’s artistic identity is deeply rooted in hyper-masculine themes, extreme martial arts prowess, and a unique narrative style that blends brutal physical combat with pseudo-scientific explanations and philosophical musings on strength. His work is characterized by a distinctive, highly detailed art style that emphasizes exaggerated musculature and intense, often grotesque, depictions of violence and physical conditioning. His real-life background in martial arts and military service lends a degree of gritty authenticity to the fighting styles and physical disciplines depicted in his manga. He is also known for writing a book on the practice of dogeza, or prostration, a recurring and often parodied element within his manga.

Keisuke Itagaki holds significant industry status as a veteran creator whose career spans over three decades. The Baki series is considered a landmark work in the martial arts and fighting manga genre, influencing numerous subsequent creators and gaining a dedicated international cult following. Its status as one of the best-selling manga series of all time cements his legacy as a commercially and culturally significant figure in the Japanese manga industry.