# The Holy Grail of Eris

The Holy Grail of Eris (エリスの聖杯, 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 twelve 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. An anime adaptation has been announced.

## Premise

A decade ago, Scarlet Castiel was executed for supposedly trying to poison the prince's lover. In the present, Constance becomes involved with helping the ghost of Scarlet figure out the chain of events that lead to her death. Leading both of them into a conspiracy that involves nations.

## Characters
### Constance Grail (コンスタンス・グレイル, Konsutansu Gureiru)

    Voiced by: Kana Ichinose
    A low ranking noble with a good heart. She was almost vilified at a party, but Scarlet briefly possessed her. She does not get along with nobles who look down on commoners and loathes baseless gossip.

### Scarlett Castiel (スカーレット・カスティエル, Sukāretto Kasutieru)

    Voiced by: Sayumi Suzushiro
    A ghost seeking answers as to why she was killed, believing that she had done nothing to warrant execution. Haughty but brilliant, Scarlet gives Constance leads on people she knew.
    Scarlet eventually discovered she was meant to mix her bloodline with the royal family, allowing her home country to take over in the future. Despite how much her father and the king adored her, they sacrificed Scarlet for the greater good of the country.

### Randolph Ulster (ランドルフ・アルスター, Randorufu Arusutā)

    Voiced by: Yōhei Azakami

### Lily Orlamunde (リリィ・オーラミュンデ, Riryi Ōramyunde)

    Voiced by: M.A.O

### Amelia Logan

    Reporter for the mayflower paper; she pops up whenever Constance is investigating. Unfortunately, her horrible investigation skills lead Amelia to make half-baked assumptions and talk over/ignore the people she is interviewing. When her boss turns down her crackpot stories, Amelia gets them printed in a different paper.
    By sheer luck, Amelia ticks off the bad guys and flees the country for her own safety.

## 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.

#### Original edition

| No. | Original release date | Original ISBN | North American release date | North American ISBN |
| 1 | November 14, 2019 | 978-4-8156-0381-6 | April 19, 2022 | 978-1-9753-3957-9 |
| 2 | May 14, 2020 | 978-4-8156-0561-2 | August 16, 2022 | 978-1-9753-3959-3 |
| 3 | October 14, 2020 | 978-4-8156-0769-2 | November 22, 2022 | 978-1-9753-3961-6 |
| 4 | March 12, 2022 | 978-4-8156-1060-9 | October 24, 2023 | 978-1-9753-7345-0 |

#### New edition

| No. | Release date | ISBN |
| 1 | November 7, 2024 | 978-4-434-34447-3 |
| 2 | November 7, 2024 | 978-4-434-34448-0 |
| 3 | November 7, 2024 | 978-4-434-34449-7 |
| 4 | November 7, 2024 | 978-4-434-34450-3 |
| 5 | November 7, 2024 | 978-4-434-34451-0 |

### 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 twelve tankōbon volumes as of March 2025. 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 a single tankōbon volume as of March 2025.

#### Volumes

| No. | Original release date | Original ISBN | North American release date | North American ISBN |
| 1 | November 12, 2019 | 978-4-7575-6370-4 | May 31, 2022 | 978-1-9753-4249-4 |
| 2 | May 12, 2020 | 978-4-7575-6643-9 | August 23, 2022 | 978-1-9753-4251-7 |
| 3 | September 7, 2020 | 978-4-7575-6824-2 | February 21, 2023 | 978-1-9753-4253-1 |
| 4 | March 5, 2021 | 978-4-7575-7130-3 | June 20, 2023 | 978-1-9753-5171-7 |
| 5 | September 7, 2021 | 978-4-7575-7444-1 | September 19, 2023 | 978-1-9753-7193-7 |
| 6 | March 7, 2022 | 978-4-7575-7773-2 | January 23, 2024 | 978-1-9753-7195-1 |
| 7 | September 7, 2022 | 978-4-7575-8119-7 | May 21, 2024 | 978-1-9753-7197-5 |
| 8 | March 7, 2023 | 978-4-7575-8450-1 | September 17, 2024 | 978-1-9753-9042-6 |
| 9 | September 7, 2023 | 978-4-7575-8772-4 | January 21, 2025 | 979-8-8554-0055-7 |
| 10 | March 7, 2024 | 978-4-7575-9085-4 | July 22, 2025 | 979-8-8554-1141-6 |
| 11 | November 7, 2024 | 978-4-7575-9505-7 | — | — |
| 12 | March 7, 2025 | 978-4-7575-9724-2 | — | — |

#### Eris no Seihai S

| No. | Original release date | Original ISBN | North American release date | North American ISBN |
| 1 | March 19, 2025 | 978-4-434-35417-5 | — | — |

### Anime

An anime adaptation was announced on October 20, 2024.