Godbeasts, also called zodiacal beasts, are animalistic or animal-like entities of such enormous power that they are almost the equivalent of true deities in the Mortal Realms.
The true deities are not the only beings with great power in the Mortal Realms. There are creatures so mighty that they can threaten whole civilisations or even the realms themselves, and many have been worshiped as gods in their time.
Few in the Mortal Realms now can say for sure if such beasts ever existed, for the godbeasts are beings whose nature is near-incomprehensible to mortals.
In the Age of Sigmar, there are legends and rumours that some of the godbeasts endure. Some are said to be active, while others are said to slumber, only to awaken some day to cause havoc when least expected. Some godbeasts are clearly tied directly to the magical energies of the Mortal Realms.
For instance, the noble and near-omniscient Dracothion, the Celestial Drake, who found Sigmar adrift in the void, clinging to the burning core of the World That Was, is somehow an inherent part of the power of Azyr, the Realm of Heavens.
Others may dwell within the individual realms, but their nature is basically inexplicable. Among these are Ghillnarad Dhor, the Prince of Flowers, who guards secrets best left forgotten for Sigmar and Alarielle.
So too are Shurihuratha, the Thought Viper, whose whispers are like a virus that infects the mind and Chimerac the Fluid, whose cast-off patchwork forms are legion.
- Warhammer Age of Sigmar Roleplay - Soulbound (RPG), pg. 258