The Source
The hide, cured and worked — the beast-folk's own, the marsh's, the poor's — the middle of the armor ladder and the one the rider expects.
The Yield
A beast gives a coat's worth; a season of curing gives the coat its shape.
In the Workshop
The leather is the armor of the man who expects a cut: it is the tier where the armor stops being a hide and starts being a choice, and the choice is the one the maker has to make right.
Cost band: apprentice to journeyman — on the ladder in The Maker's Hand, the material is the floor, and the floor is the one the mine or the marsh or the tree has to give. Recipes that take it: tailoring, the armor ladder