A Purgatory is the interface between a Sanctum and the Outer World: where a transition is made between the contaminated world into the pure, safe world beyond. In a Purgatory, all sorts of rituals and processes of cleansing are carried out, to purify the entrant so that they may pass through to the Sanctum without bringing in contamination from the Outer World. Conversely, someone leaving the Sanctum will have their ritual protection renewed to allow them to enter the Outer World and remain proof against its contaminations