Makiburo is the original creator behind the anime and manga series The One Within the Villainess. Makiburo began as an indie web novel author, first serializing the story on the user-generated novel publishing website Shōsetsuka ni Narō for a short period in May 2020. The series was later acquired by the publisher Ichijinsha, which began releasing it as a light novel with illustrations by Mai Murasaki in February 2021. Two volumes of the light novel had been released as of February 2024.

The story centers on Remilia, a girl who is mistreated and grows up to embody the role of a villainess in an otome game setting. Her body is taken over by a reincarnating player named Emi, who becomes her sole source of affection. When Emi is betrayed by the game's other characters and falls into despair, the original villainess Remilia reawakens from within and vows a ruthless revenge against those who harmed Emi. Makiburo has stated that the inspiration came from a desire to see a story about a true villainess who remains a villain yet still finds happiness, as opposed to narratives where the character reforms or is revealed to be good at heart.

A manga adaptation of The One Within the Villainess, illustrated by Nazuna Shiraume, began serialization on the Pixiv Comic website under Ichijinsha's Comic Lake brand in November 2021. The manga has been collected into multiple tankōbon volumes, with five volumes released as of November 2024. The series gained significant popularity, with the manga adaptation ranking in the Next Manga Awards and the Web Manga General Election, and it was ranked eighth in AnimeJapan's "Manga We Want to See Animated" poll in 2025. An anime adaptation has been announced as being in progress. Beyond this debut title, Makiburo has also garnered a following for other works such as Unaware Genius Girl Is Oblivious and Elizabeth is out of Love.