Fummy is the creator credited with the original story for the manga The Witch's House - The Diary of Ellen. The individual is known for developing the original horror puzzle game The Witch's House, which served as the foundation for the subsequent manga and novel adaptations. The game was created using RPG Maker VX and released in October 2012.

In addition to game development, Fummy is also a VOCALOID music producer, known for creating songs with dark or sad themes primarily using the vocal synth Hatsune Miku.

The original game, The Witch's House, casts the player as a girl named Viola who becomes trapped in a witch's house and must find a way to escape. The prequel novel, The Witch's House - The Diary of Ellen, was written by Fummy and published by Kadokawa in October 2013 with illustrations by Oguchi. This novel tells the story of how the character Ellen became a witch, providing backstory to the events of the game.

The manga adaptation, The Witch's House - The Diary of Ellen, was illustrated by Yuna Kagesaki, with Fummy credited as the original story creator. The manga was serialized in Kadokawa's Monthly Dragon Age magazine from June 2017 to February 2018 and compiled into two volumes. The series was published in English by Yen Press, with digital simulpub beginning in August 2017 and print volumes released in January and June 2019.