The creator known as Murasaki, also credited under the name Harumurasaki, is the original creator behind the supernatural mystery franchise The Case Book of Arne. This person is the scenario writer for the original video game and the writer for its upcoming anime television adaptation.

The Case Book of Arne began as a Japanese mystery adventure video game developed by Harumurasaki and published by Vaka Game Magazine. The game was created using RPG Maker and was first released as freeware in November 2017, later becoming available on Steam. The story follows Arne Neuntöte, a vampire detective who wields supernatural powers, and Lynn Reinweiß, a nobleman's daughter with a fascination for vampires, as they join forces to solve bloody mysteries in a city called Lügenberg where non-humans reside.

In 2018, Kadokawa began publishing a manga adaptation of The Case Book of Arne in their shojo manga magazine Monthly Comic Gene, with artwork provided by Soraho Ina. This manga adaptation completed its run in March 2022 and was collected into four tankobon volumes. In November 2024, an anime television series adaptation was announced, with Murasaki confirmed to be handling series composition for the project while original character designer Harutarou returns to provide character designs.

Beyond The Case Book of Arne, no verified information is available about other notable original works by Murasaki, the creator's personal background, recurring themes or artistic identity in their body of work, or their broader significance within the anime and manga industry.