Ichika Isshiki is a Japanese author best known as the original creator of the light novel and manga series Berserk of Gluttony. Isshiki began their writing career not as a professional novelist, but as a corporate employee who started writing as a personal pursuit. The initial inspiration to write came later in life, beginning with short texts that gradually increased in length until the decision was made to pursue a longer project. The creative process was also influenced by classic role-playing games such as Dragon Quest and Final Fantasy, which helped shape the fantasy world of the series.

The origin of Berserk of Gluttony traces back to a web novel that Isshiki began publishing on the user-generated site Shōsetsuka ni Narō in January 2017. The series quickly gained attention and was picked up by the Japanese publisher Micro Magazine, leading to its official debut as a light novel in November 2017 with illustrations provided by the artist fame. The series later moved to the Kakuyomu platform in March 2022. The central concept of the series, which reinterprets the seven deadly sins with a focus on the skill of Gluttony, was developed with the intention of exploring a theme common in light novels while offering a protagonist who starts from a position of weakness and grows over time. The character of the sword Greed was specifically created to serve as a permanent guide and conversational partner for the main character, Fate, providing a dynamic personality opposite to his own naive nature.

The success of the original light novel led to a significant expansion of the franchise across multiple media. A manga adaptation, illustrated by Daisuke Takino, began serialization in Micro Magazine's online Comic Ride platform in March 2018. The series has seen international publication, with English releases by Seven Seas Entertainment and French releases by Mahō. An anime television series adaptation produced by A.C.G.T aired from October to December 2023, bringing the story to a wider audience. Additionally, the series has been adapted into a webtoon format, demonstrating its broad appeal and successful transition across different storytelling mediums.

Isshiki's approach to storytelling emphasizes character growth and the development of strong, independent female characters such as Roxy, Myne, and Eris, who were intentionally designed to influence the protagonist's journey with their distinct values and personal struggles. The recurring theme of power with a cost is central to the work, as the protagonist's Gluttony skill provides strength but carries the risk of consuming him entirely. The series has achieved international success, with the light novel selling nearly one million copies and being translated for markets in Europe, the United States, and Asia, establishing Isshiki as a notable creator within the fantasy light novel genre.