Netherstone, Celestialite, and Titan metal:
Netherstone: Netherstone is a purple crystal, it's connected to the Netherworld/is from the Netherworld. Strengthens demons and their powers/amplifies their powers. It forms in weak spots between the Netherworld and Earth examples of this include demon battlefields, the final resting place of powerful demons, and gateways however it’s all over the Netherworld. Some Netherstones act as demon coffins. Netherstone is pretty sacred to demons.
Celestialite: The "Celestial realm’s version of Netherstone", it comes from the (compressed) bones of dead celestials. Very rare. Can undo demonic illusions, smaller curses, and demonic influence.
Titan metal: Used mostly as chains. The only thing on Earth that can trap/harm celestials, it was made in ancient times by titans to fight the celestials, it's used nowadays by demon hunters to help trap demons/mythical creatures.
