Demoness of Despair — the threshold of a demigod. The canon names no new abilities here: instead, everything that was accumulated — the witch's craft, pleasure, ailments — is amplified at once and strongly.
As a demigod who has received a share of divinity, she is able to manifest an incomplete mythic form and turn into an unfinished gorgon, if she is ready to disregard the consequences.
The method of action is extremely brief and thereby terrible: to experience despair — and to bring despair to others. The step requires not mastery, but a state: the bearer must know what she is talking about.
The advancement ritual translates this into numbers: a plague that has engulfed more than thirty thousand people. The more that die, the stronger the despair and suffering, the better the ritual will work.
The composition matches: the venomous sac of the Snake — Mother of the Plague, the crystal of the silver hunter, a fresh branch of mistletoe, and the blood of seven who died of various pestilences.