Satoru Yamaguchi is the Japanese author and original creator of the light novel series My Next Life as a Villainess: All Routes Lead to Doom!. The series began as a web novel serialized online in July 2014 on the user-generated publishing website Shōsetsuka ni Narō. It was later acquired by Ichijinsha, which published the first light novel volume in August 2015 under its Ichijinsha Bunko Iris imprint.

Yamaguchi is credited as the original creator behind the franchise's various media adaptations. These include the manga adaptation illustrated by Nami Hidaka, which began serialization in Ichijinsha's Monthly Comic Zero Sum magazine in August 2017. Yamaguchi is also credited for the spin-off manga My Next Life as a Villainess Side Story: On the Verge of Doom!, illustrated by Nishi, which ran from November 2019 to July 2021. Additionally, Yamaguchi is listed as the original creator for the anthology manga My Next Life as a Villainess Side Story: Girls Patch, a collection of short stories focusing on the female characters of the series.

In anime, Yamaguchi is credited as the original author for the television series My Next Life as a Villainess: All Routes Lead to Doom!, which aired from April to June 2020, and its second season, My Next Life as a Villainess: All Routes Lead to Doom! X, which aired from July to September 2021. An anime film was also released in December 2023, with Yamaguchi again credited as the original creator.

The central narrative, for which Yamaguchi is known, follows Katarina Claes, a young noblewoman who reincarnates into the world of an otome game as the villainess character. Using her knowledge of the game, she attempts to avoid the catastrophic bad endings that await her, which typically involve exile or death. The series is known for its blend of isekai, romantic comedy, and reverse harem genres, with the protagonist's dense and good-natured personality being a hallmark of the story. The franchise has been commercially successful, with the light novel series reaching fifteen volumes as of July 2025, and the manga adaptation collected into twelve volumes.