nozomanu fushi no boukensha

The Unwanted Undead Adventurer (Japanese: 望まぬ不死の冒険者, Hepburn: Nozomanu Fushi no Bōkensha) is a Japanese light novel series written by Yū Okano and illustrated by Jaian. It has been serialized online via the user-generated novel publishing website Shōsetsuka ni Narō since September 2016. It was later acquired by Overlap, who have published thirteen volumes since October 2017 under their Overlap Novels imprint.

A manga adaptation illustrated by Haiji Nakasone has been serialized in Overlap's Comic Gardo website since November 2017, with its chapters collected into twelve tankōbon volumes as of December 2023. An anime television series adaptation produced by Connect aired from January to March 2024.

https://en.wikipedia.org/wiki/The_Unwanted_Undead_Adventurer