Rituals (9e)

Rituals are special procedures that characters can learn that allow them to do things far beyond their normal capacity, such as heal grave illnesses, banish evil forces, travel between worlds, raise the dead, or any other kind of amazing result that would otherwise be too powerful for frequent use in the game's narrative.

Once a character has learned a ritual, then they can perform it whenever they want, provided that they have the right ingredients. Ingredients can be anything from special substances (dragon blood, volcanic glass, holy water, the eye of a cyclops, etc.) to particular artifacts, or specific locations.

It is up to the DM to decide on the ingredients for a particular ritual, but once they have been decided, they should not be changed unless absolutely necessary. The players may not appreciate spending a lot of effort for a ritual that only works once!