Velvet bomb
Gwen's father's tea, and the soul-goo nobody knew was in it
A remedy Gwen’s father made, and the thing she has reached for when the Magiauredo turns bad. She drank it for years without knowing what it held.
It came out at the Crack, when she was sick in the middle of a room and Koa saw the faint light in it. She had thrown up ooze. She stood there working backwards through it (the velvet bomb; there are trace amounts in the velvet bomb, but not that much; I forgot there was some in there, but not that much), and that was how the tea stopped being a comfort and became a question.
The question got larger, not smaller. Her sickness kills in months to a few years and hers had been stable for years, and the tea was the reason everyone had settled on. Later nobody was sure of that any more, and what had actually been holding the disease off was looking less like a spoonful in a cup and more like the raw stuff itself. Her father is not here to be asked how it got in.