Kumo Kagyu is a Japanese author and creator best known for originating the dark fantasy franchise Goblin Slayer. He was born on July 3, 1989, in Tokyo. Before his career as a writer, Kagyu worked as a production assistant at the animation studio White Fox. He maintains a private personal life, and his real name has not been publicly disclosed.

Kagyu began writing what would become Goblin Slayer online in October 2012. The series was later picked up for formal publication as a light novel in 2014, with the first volume released in print in February 2016. The story follows a single-minded adventurer dedicated to exterminating goblins, creatures often dismissed as weak but portrayed as a significant and cruel threat. The light novel series has received recognition, including being selected for the GA Bunko Grand Prize and placing third in the Fujimi Fantasia Grand Prize.

From this initial light novel, the Goblin Slayer property expanded into a multi-platform franchise. A manga adaptation illustrated by Kōsuke Kurose began publication in 2016. An anime television series adaptation followed. Kagyu is also credited as the original creator for several spin-off manga series set in the same world, including Goblin Slayer Side Story: Year One, Goblin Slayer: Brand New Day, and Goblin Slayer: Daikatana. These works explore different time periods and characters within the franchise's setting.

Beyond the Goblin Slayer universe, Kagyu launched another light novel series titled Blade & Bastard in December 2022, published under the DRE Novels imprint. The series features illustrations by so-bin, the artist known for the Overlord light novels. A manga adaptation illustrated by Makoto Fuugetsu began in June 2023. In October 2024, an anime adaptation for Blade & Bastard was announced. The story follows Iarumas, an amnesiac adventurer who recovers corpses in a deadly dungeon, and his encounter with a feral young swordswoman named Garbage.

Thematically, Kumo Kagyu's work is rooted in dark fantasy, often exploring grim and violent subject matter. His stories tend to feature protagonists facing extreme situations, with recurring elements including death, survival, and pragmatic, utilitarian approaches to adventuring. He has cited Western fantasy works as influences on his writing, including J.R.R. Tolkien and George R.R. Martin, as well as the manga of Kentaro Miura and role-playing games like Dungeons & Dragons. The explicit violence in Goblin Slayer has generated discussion, with Kagyu stating his intent was to highlight the cruelty of the goblin antagonists and the importance of protecting vulnerable characters rather than simply aiming to shock readers.

Kumo Kagyu has established himself as a significant creator in contemporary Japanese dark fantasy. His signature work, Goblin Slayer, has grown from a web novel into a successful multimedia franchise encompassing light novels, multiple manga series, and an anime adaptation. The announcement of an anime for his newer series Blade & Bastard indicates his continued relevance and productivity within the industry.