A catalyst is a small surge in ambiance that jumpstarts a ritual. Usually, Catalysts are made out of paper tags, which would be burned from one end. When an object is quickly burned, the ambiance contained inside is forced to condense into a smaller and smaller space. Eventually the ambiance runs out of matter to inhabit and “pops,” releasing a sudden rush of energy.
Heroes can catalyze a ritual without using a tag because, unlike normal people, they can manipulate the ambiance held in their bodies. By consciously releasing a burst of ambiance, heroes can catalyze a ritual on command.