Three things are never accepted at the Hour of the Rat: the life force of the living (to guard against dark cultivators), the obsessions of one's closest kin (to guard against mirror demons), and reflections in mirrors (to guard against identity swaps).
The iron law of trade: every item pawned must have collateral of equal value. To reclaim it, one must pay “interest in time” (for example, pawn one night's memories and pay three days of one's lifespan to get them back).
Spatial rule: the pawnshop's interior changes with the phases of the moon. At the full moon, it connects to the “Mirror Abyss,” the ultimate battlefield.
