The Holy Grail of Eris
The Holy Grail of Eris 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 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. An anime television series adaptation produced by Ashi Productions premiered in January 2026.
Plot
A decade ago, Scarlett Castiel was executed for supposedly trying to poison the prince's lover. In the present, Constance Grail becomes involved with helping the ghost of Scarlett figure out the chain of events that lead to her death. Leading both of them into a conspiracy that involves nations.Characters
;Constance Grail;Scarlett Castiel
;Randolph Ulster
;Lily Orlamunde
;Cecilia Adelbide
;Enrique Adelbide
;Dominic Harmsworth
Media
Light novels
Written by Kujira Tokiwa, The Holy Grail of Eris was serialized online on the user-generated novel publishing website Shōsetsuka ni Narō from October 16, 2017, to August 4, 2018. It was later acquired by SB Creative who published four volumes with illustrations by Yuunagi under their GA Novel imprint from November 14, 2019, to March 12, 2022. The GA Novel volumes are licensed in North America by Yen Press.A new edition published under Drecom Media's DRE Novels light novel imprint was published with five volumes releasing on November 7, 2024.
Manga
A manga adaptation illustrated by Hinase Momoyama began serialization on Square Enix's Manga Up! manga website and app on November 3, 2019. The manga's chapters have been collected into fourteen volumes as of January 2026. The manga adaptation is also licensed in North America by Yen Press.A sequel manga illustrated by S.Kosugi, titled Eris no Seihai S, published its "0th" chapter on Drecom Media's DRE Comics website on October 18, 2024. It later began serialization on November 1, 2024. The sequel's chapters have been collected into two volumes as of September 2025.
Anime
An anime adaptation was announced on October 20, 2024, which was later revealed to be a television series produced by Ashi Productions and directed by, with series composition and episode scripts written by and characters designed by Chie Kawaguchi. The series premiered on January 8, 2026, on TBS and its affiliates, as well as BS11. The opening theme song is "Happy Ever After feat., performed by Reina Washio, while the ending theme song is "Camellia", performed by Yukari Tamura.Crunchyroll is streaming the series. Plus Media Networks Asia licensed the series in Southeast Asia and broadcasts it on Aniplus Asia.