The Holy Grail of Eris
Eris no Seiha / Eris no Seihai: Konyaku Haki Sareta Reijou ha / Kitai no Akujo / Tasukerareta Daishou Toshite Fukushuu ni Tsuki Awasaremasu / Eris no Seihai: Konyaku Haki Sareta Reijou wa / Kidai no Akujo ni Tasukerareta Daisho Toshite Fukushuu ni Tsuki / エリスの聖杯 ～婚約破棄された令嬢は、稀代の悪女に助けられた代償として復讐に付き合わされます～
Connie, a viscount’s daughter valued for her honesty, meets Scarlet Castiel, the notorious villain executed ten years earlier, at a night party. Their encounter begins a story that should have ended with Scarlet’s death. The two women initially join forces because they are interested in the same things. They become true partners as they seek the truth behind a vast conspiracy from the past, one that continues to cast a shadow over the present.