The official website for the TV anime adaptation of The Holy Grail of Eris announced the main staff and cast of the series. In addition, a new key visual and promotional video were released.

The cast of The Holy Grail of Eris anime includes:
- Kana Ichinose as Constance Grail
- Sayumi Suzushiro as Scarlett Castiel
- Yōhei Azakami as Randolph Ulster
- M.A.O as Lily Orlamunde
The staff includes:
- Director: “Morita to Junpei”
- Series Composition, Script: Kenichi Yamashita
- Character Design: Chie Kawaguchi
- Sub-Character Design: Jun Yukawa
- Art Director: Nobuhito Sue (Kusanagi)
- Color Design: Aiko Yamagami (T.D.I.)
- Director of Photography: Yūko Kamahara (T.D.F.)
- Editing: Yuriko Sano (T.A.P.)
- Sound Director: Yūichi Morita
- Production: Good Smile Film / DRE Pictures
- Animation Production: Ashi Productions
Kujira Tokiwa and Yuunagi launched The Holy Grail of Eris light novel on the Shōsetsuka ni Narō website in 2017. Momoyama launched a manga adaptation on Square Enix’s Manga UP! platform in 2019. Yen Press publishes the manga physically, while Manga UP! publishes the manga digitally. A sequel manga, The Holy Grail of Eris -SEQUEL-, was launched on October 18, 2024 by S.Kosugi.
Lastly, here’s an overview of the series, via Yen Press:
Connie is a young noblewoman whose only standout quality is her sincerity. Maybe that’s why she loses her fiancée and gets framed for a crime in the span of one night. Just as all hope seems lost, the ghost of an infamous villainess who was executed years ago possesses her and clears her name. With her incomparable charisma and intelligence, the spirit of Scarlet Castiel turns the tables in the blink of an eye. In return, Connie insists that she help uncover the truth surrounding her new benefactor’s untimely death and a conspiracy that continues to this very day!