Black Mould
The black mould is the growth of the Rotting Crown, the Cast-Out who was once the Keeper of the Line. It furs the bone of the Crown’s face, trails from its crown down its neck, and falls behind it as the Mould Trail, a path of soft ground where nothing living keeps its shape. It is not a fungus that grows on its own; it is the Crown’s rot made visible.
Appearance
On the Crown it is a short, dense black fur, like soot on a damp wall, close over the bare bone of the face and thicker in the hollows of the eyes. Where the living growth of the crown pulses its sickly green, the mould runs from it in wet black threads down the neck and into the mouldering velvet. It glistens and drips.
On the ground it shows as black streaks and spreading patches in the soft earth, fine as cobweb at the edges. The Trail smells of wet earth, decay, and old blood, and it drips: from leaves, from eaves, from the hems of those who have walked through it.
Habitat and Range
The mould lives on the Crown and follows it. The Trail runs wherever it has walked, and lies thickest around the houses it rules, where the soil goes soft with their rot. It also comes with the Crown out of the crypts of the Ashen Wastes, whose decay it draws on.
Behaviour and Temperament
It has no mind. It spreads where the Crown passes and stays where the Crown stays. In a house the Crown keeps, it creeps in season after season: into the cellar, the family crypt, the seams of the heirlooms, and the field margins, until the house and its land are one soft, black ruin.
Abilities
Where the Trail falls, flowers wilt at once and trees slump to black sludge. The ground goes soft and spongy underfoot and will not hold a post. Around the Crown’s Rot Field the mould runs ahead of the decay, so that food blackens before it rots and a field is lost before its crop is grown.
Life Cycle
It is born from the Crown and does not seed itself. When the Crown leaves a place, the Trail stops spreading, and it can be dug out and burned. When a line it has bound at last slumps into black sludge, the mould is all that grows on what is left.
Uses and Dangers
It gives nothing, and it takes land and the living it touches. Its worst danger is that it marks a house that has already let the Crown in, and by then the house rarely wants to be told.
Lore and Belief
Old houses call black mould in the family crypt a sign that the ancestors are restless, and some read it as a blessing on the line. The Crown’s victims are told that the rot is the price of continuity, and they believe it. Farmers say the cure is to plant something new where the Trail has run, and this is closer to the truth than most lore: what weakens the Crown is a seed in fresh soil, an inheritance set down, a house founded instead of inherited.
Grave-robbers who break into a mould-blackened crypt for its grave-goods are said to carry the rot home with them, and in the old houses' country a thief’s family is known by the black on its doorposts.