Grisial is a type of energy source found only in the oldest reaches of Revaliir. They look like lumps of blue, glowing crystal, and are highly poisonous to anyone who touches them without proper safety measures. However, when hooked up to a magical matrix that can sustain them, these crystals have been known to provide virtually limitless power.

Grisial were first discovered in Railoch, where the excavation crew all died in days of first contact. They are rumored to be the power source that was originally used in a prototype for Karith, but that city exploded after a few short days in the air. Thus far, no one has succeeded in replicating the process used by ancients to construct the many Grisial Portals that dot the landscape. They and their use are one of Revaliir's great mysteries.