The Holy Grail of Eris | GOGOAnime

Synopsis:

It is well known that aristocrats will do anything for power; lying, manipulation, and extortion are common tactics. However, one family is exempt from this generalization: House Grail, whose core principles are truth and honesty. Their youngest daughter, Constance Grell, is as moral as the rest of her family, always believing in doing the right thing and helping those in need.

However, when her fiancé cheats on her with another woman, these ideals fail her. Framed by her lover, anticipating her downfall, Constance has no one to listen to her pleas for justice. Everyone turns a blind eye, except for one—the infamous spirit of Scarlet Castiel—who possesses Constance and turns the tables on her accuser. However, this help comes at a price.

Ten years ago, Scarlett was executed for the attempted murder of Princess Cecilia. But it was a setup; as ruthless and tough as Scarlett was, she never stooped so low as to use poison. She has no idea who orchestrated her condemnation, but Scarlett demands that Constance—as the only person who can see her—help her take revenge on all those who have wronged her.