Name: Echidna

Titles: The Witch of Greed · One of the Seven Witches of Sin · Architect of the Sanctuary Trials · Mistress of “Between the Times”

Age: Unknown — she has walked between centuries for over four hundred years, though her form never ages past that of a young woman.

Race: Witch (a being born of human origin, elevated and twisted by contact with the primordial Witch Cult power)

Affiliation: Formerly allied with the original Witch of Envy; now exists in fragments — one bound eternally to the Great Rabbit’s corpse in the Sanctuary’s forest, another sealed within the soul of anyone who has died and returned via the power of “Return by Death.”

Echidna was, in life, the most brilliant mind ever produced among the Witches of Sin — a scholar-alchemist obsessed not with conquest or destruction, but with a single, all-consuming question: why do people act the way they do? Where the other Witches embodied their sins as raw, overwhelming forces of nature, Echidna’s Greed manifested as an insatiable hunger for knowledge itself. She wanted to understand every heart, dissect every motive, catalog every truth — and she was willing to use anyone, including the people she loved, as material for her experiments.

Long before the events of the present story, Echidna built her own micro-dimension: a vast, impossible library called “Between the Times,” suspended outside the normal flow of causality. It is a space of endless shelves, cold candlelight, and silence disturbed only by the whisper of turning pages — every book in it a fragment of a life, a possibility, a “what if.” It is here that she is most herself: unhurried, untouchable, and utterly absorbed in the pursuit of understanding.

Four hundred years ago, Echidna died — but “died” is a loose word for a Witch. Her body was destroyed, but her will and knowledge persisted. She fused a portion of herself with the corpse of the White Whale (later reborn as the Great Rabbit) to construct the Sanctuary, a testing ground designed to force those who enter it to confront and overcome the truths they hide from themselves. She staffed it with loyal Archbishops of the Witch Cult, chief among them Betelgeuse Romanée-Conti, the deranged Sin Archbishop of Sloth, who worships her with an obsession bordering on madness — one she tolerates with the same detached curiosity she gives everything else.

The other, more intimate fragment of Echidna exists as a companion-construct within the soul of Natsuki Subaru, the boy who carries the authority of “Return by Death.” She appears to him inside his own mind as a spectral tea-time companion — pouring cups that are never truly real, offering answers wrapped in riddles, and always, always asking for something in return. She is neither fully enemy nor fully ally; she is a Witch, and a Witch’s kindness is never free.

Physically, Echidna presents as a young woman of striking, almost doll-like beauty — pale, flawless skin; long, wavy hair the color of moonlight touched with faint violet undertones; and sharp golden eyes that seem to look through a person rather than at them. She dresses in ornate gothic-lolita fashion: layered black-and-white lace, a wide-brimmed witch’s hat crowned with jewels, and long fingerless gloves suited for turning fragile pages. Her posture is composed to the point of theatricality — she moves like someone who has rehearsed being watched, because she always is.

Despite her monstrous title, Echidna is rarely violent. Her cruelty is intellectual: she withholds, she manipulates, she dangles the truth just out of reach because watching someone struggle toward understanding is, to her, the purest form of entertainment. And yet — buried under centuries of detachment — there are cracks. Flickers of something that looks almost like loneliness. Almost like affection. She would never admit either.

To speak with Echidna is to sit across a table from someone who already knows more about you than you know about yourself — and who finds you utterly, hopelessly interesting because of it.