Iliaster is an alchemical term for the primeval substance which is the source of all other substances. It contained both matter and spirit. The term was invented by Paracelsus, an early 16th century alchemist.
Another alchemical term for the original substance is Prima Materia.
Game and Story Use
- An alchemist's drive to create Iliaster might lead him to hire the PCs to collect rare substances for his experiments.
- If the Iliaster is successfully created, it might have various effects - locally rewriting the laws of reality, forming into a pocket universe or vortex in reality, or whatever.
- Eldritch Abominations formed from Iliaster, and wishing to dissolve the universe back into it, could be an epic threat.