Masasumi Kakizaki is a Japanese manga artist born on May 18, 1978, in Monbetsu, on the northern island of Hokkaido. His path to becoming a creator was unconventional, as his initial ambition was to be a novelist. After realizing his writing alone was not strong enough, he began drawing in his twenties, finding that his visual skills held more promise. He made his professional debut in March 2001 with a short story titled Two Tops, published in Shogakukan's Bessatsu Young Sunday magazine.

Kakizaki's first serialized work was the science fiction action series X-Gene, which ran from 2001 to 2002. For this project, he provided the artwork for a story written by Kentaro Fumitsuki. This collaboration established a pattern for his early career, as he soon began what would become his most famous work, Rainbow: Nisha Rokubō no Shichinin. Serialized from 2003 to 2010, Rainbow was a historical drama set in a brutal reformatory in post-World War II Japan. With a script by writer George Abe, Kakizaki's detailed and expressive artwork brought the story of seven young delinquents to life. The series was a critical and popular success, winning the 51st Shogakukan Manga Award in the general category in 2005. Its popularity led to a 26-episode anime adaptation produced by the acclaimed studio Madhouse.

Following the conclusion of Rainbow, Kakizaki began creating his own stories, often exploring distinct genres through short, focused works. In 2008, during a hiatus in Rainbow's publication, he wrote and illustrated Kansen Rettō, a seven-chapter medical thriller about a deadly virus outbreak, which was later adapted into a live-action film in 2009. He then turned to horror with the one-volume work Hideout in 2010, a claustrophobic thriller that he has stated was inspired by his love of Stephen King novels and horror cinema.

Since 2011, Kakizaki has continued to build a diverse body of work, frequently writing his own scripts. He launched two significant series that year. Green Blood, published in Kodansha's Weekly Young Magazine from 2011 to 2013, was a five-volume western set in the 19th-century slums of New York City, drawing clear inspiration from the spaghetti western films of Sergio Leone. At the same time, he began Bestiarius, a historical fantasy series set in the Roman Empire that follows gladiators who fight alongside mythical creatures. This series, which ran from 2011 to 2018, represented his first work aimed at a younger shonen demographic. More recently, he has adapted the film Wife of a Spy into a two-volume manga (2020-2021) and created The Tree of Death: Yomotsuhegui (2021-2023), a horror series for Kodansha.

Kakizaki's artistic identity is defined by a strong cinematic quality. He is a self-described cinephile whose work is heavily influenced by film, from the composition of his panels to the genres he chooses to explore. His drawing style is characterized by a precise use of chiaroscuro—strong contrasts between light and shadow—to create a dense, atmospheric, and highly expressive visual experience. Rather than sticking to a single genre, his career is marked by a willingness to master and reinvent the codes of different cinematic traditions, from horror and western to historical epic and science fiction.

Masasumi Kakizaki holds a significant place in the manga industry as a celebrated illustrator and an auteur capable of weaving complex, dark narratives across a wide range of genres. His work is recognized for its technical precision and its successful translation of cinematic influences into the language of manga. He is a frequent guest at international manga festivals, with notable appearances at events in Spain, including Expomanga Madrid in 2016 and the Salón del Manga de Barcelona in 2017.