Midori Yūma is a Japanese novelist and manga writer, best known as the original creator of the supernatural romance and culinary series Kakuriyo: Bed & Breakfast for Spirits. Yūma is also associated with the pen name Kappa Domei and began their career as a writer in 2013 before gaining wider recognition. The author's birthday is listed as April 9, though the specific year of birth is not publicly documented.

Yūma is the credited author of the original light novel series Kakuriyo no Yadomeshi, which began publication on April 15, 2015, under Fujimi Shobo's Fujimi L Bunko imprint. The series, which features illustrations by Laruha, concluded its main storyline after thirteen volumes, with the final volume released in October 2025. The light novel serves as the foundational source material for the broader Kakuriyo franchise, which has been adapted into multiple manga series and an anime television series.

The first manga adaptation of Yūma's work, illustrated by Waco Ioka, began serialization in Enterbrain's B's Log Comic magazine on April 30, 2016, and is licensed for English release by Viz Media. A second manga adaptation, illustrated by Tsugaru Toba, was serialized in Kodansha's Monthly Shōnen Sirius from January 2023 to January 2026. The story follows Aoi Tsubaki, a college student with the ability to see ayakashi spirits, who is taken to the Hidden Realm to repay her late grandfather's debt to an ogre innkeeper named Odanna. Rather than accept his marriage proposal, she negotiates to work at his inn, the Tenjin'ya, using her culinary skills to build relationships with the spirit world.

An anime television series adaptation produced by Gonzo aired from April to September 2018, spanning 26 episodes. A second season, produced by Gonzo and Makaria, aired from October to December 2025. Yūma is officially credited as the original creator for both anime seasons.

Beyond the Kakuriyo series, Yūma has authored several other light novel and manga works. These include Tales of Reincarnation in Maydare: This World's Worst Witch, which began publication in 2019, The Ayakashi Hunter's Tainted Bride, which started in 2023, the Asakusa Oniyome Nikki series which began in 2016, and Torii no Mukou wa, Shiranai Sekai deshita. which ran from 2016 to 2021. Yūma is also the author of the Minazuki-ke no Iinazuke series which began in 2022. These works consistently incorporate elements of Japanese folklore, supernatural romance, and themes of human-spirit world interaction, establishing a recognizable artistic identity centered on ayakashi and fantasy settings.