Echidna (エキドナ) was the Witch of Greed. Mentioned throughout the series, particularly for her connection to Roswaal and Beatrice, she formally debuted in Arc 4 as a major supporting character and later secondary antagonist. She was a woman who, in her curiosity, used her Authority of Greed in an effort to learn anything and everything about the world, and she was the overseer of the Sanctuary’s Castle of Dreams who preserved the souls of the other Witches of Sin within it. 