The Holy Grail of Eris (Japanese: エリスの聖杯, Hepburn: Erisu no Seihai) is a Japanese light novel series written by Kujira Tokiwa and illustrated by Yuunagi. It was serialized online from October 2017 to August 2018 on the user-generated novel publishing website Shōsetsuka ni Narō. It was later acquired by SB Creative, who have published four volumes from November 2019 to March 2022 under their GA Novel imprint. A manga adaptation with art by Hinase Momoyama has been serialized online via Square Enix's Manga Up! website since November 2019 and been collected in fourteen tankōbon volumes. A new edition of the light novel series by the same author and illustrator was published in five volumes by Drecom Media in November 2024 under their DRE Novels imprint. A sixth volume and a digital short story collection were released in January 2026. An anime television series adaptation produced by Ashi Productions premiered in January 2026.
