Hiro Ainana is a Japanese author and creator known for the fantasy series Death March to the Parallel World Rhapsody. Ainana first launched the story as a web novel on the user-generated content site Shōsetsuka ni Narō in 2013. The series was later acquired for print publication, with the first light novel volume released in March 2014 by Fujimi Shobo, featuring illustrations by shri.

Ainana is credited as the original story creator for the series' various manga adaptations. The main manga adaptation, illustrated by Ayamegumu, began serialization in Kadokawa's Age Premium magazine in December 2014 before moving to Monthly Dragon Age. Yen Press has published both the light novels and the manga adaptation in English. Beyond the main series, Ainana's original story also served as the basis for spin-off manga works, including Death Marching to the Parallel World Rhapsody Ex, a prequel manga by Akira Segami that ran from February to July 2018.

The series follows a 29-year-old programmer who falls asleep during a period of intense work known as a "death march" and awakens in a fantasy world with game-like powers, where he decides to pursue a leisurely life of sightseeing rather than grand adventures. The franchise expanded with a 12-episode anime television adaptation by Silver Link that aired in January 2018. In November 2024, Kadokawa announced that a sequel anime is in production.

Ainana concluded the web novel series in March 2020, though side stories continued to be published online, with the print novels planned to have a different conclusion than the web version.