Kōsuke Unagi is a Japanese writer known primarily as the original creator of the light novel series I Left My A-Rank Party to Help My Former Students Reach the Dungeon Depths. Unagi began the story as a web novel, serializing it on the user-generated novel publishing website Shōsetsuka ni Narō from October 2020 to February 2025. The series was later acquired by Kodansha, which published five light novel volumes from June 2021 to February 2025 under its Kodansha Ranobe Books imprint, with illustrations by Super Zombie.

The story’s expansion into other media forms constitutes Unagi’s most significant body of credited work. A manga adaptation, with art by Yūri, began serialization in Kodansha’s Magazine Pocket online platform in June 2021 and has been collected into multiple tankōbon volumes. An anime television series adaptation produced by Bandai Namco Pictures aired from January to June 2025, with a second season announced following the conclusion of the first. The franchise has since expanded further, with a video game adaptation announced by developer Com2us in early 2026.

As an author, Unagi’s known work falls within the fantasy and adventure genres, focusing on themes of teamwork, the recognition of support roles, and protagonists who find greater fulfillment after leaving toxic environments. The original series follows a support mage who departs from a high-ranking but dismissive adventuring party to lead a group of former students, achieving success through collaboration and mutual respect. This premise has formed the basis for all subsequent adaptations, with Unagi credited as the original story author across the light novel, manga, and anime projects.

The commercial and multimedia success of this single property marks Unagi’s primary industry significance, with the franchise achieving a rare expansion across print, broadcast animation, and interactive media within a few years of its initial publication.