From Scratchpad

A Zantruk is a large metal tablet made by the Kruktur which possesses great powers due to its extremely advanced technology. Zantruks generally have military uses, but a few rare ones were used for other pursuits.

The technology of a Zantruk can not be explained by common civilizations, who often dismiss it as "magic." Today, no Zantruks remain outside the possession of the Kruktur, the last one having been used to end the Shadow War and banish the Fulna to their universe.