Publisher's blurb:
Before humans, dwarves, or even elves existed, the behemoths walked the material plane. Widely considered one of the first beings shaped by the gods, behemoths were so mighty they unintentionally threatened the other races intended to populate creation. With no mortal force capable of taming them, the gods stepped in directly to capture the beasts and take them to celestial realms where they could serve another purpose.
Yet the presence of behemoths has not been forgotten. Every few millenia someone will claim to have seen a behemoth the gods missed in their initial sweep. Even more concerning are the beasts who seem to have escaped from celestial planes, still wearing the harnesses forged by the gods to control their actions.
Behemoths are massive but solitary creatures, typically driven into a rage at the mere sight of another creature in their territory. While they are strict herbivores, sentient beings give them a wide berth - behemoths will often swallow other creatures, damage them with acid from one of their stomachs, and vomit them out in an effort to disorient them. A behemoth left to itself might eat an entire forest or drink up a lake, but allowing that is safer than confronting one in combat.
Or at least it was. Some “divine behemoths” who escaped their masters still wear their celestial harnesses. If a mortal could take hold of this harness, they would become master of a force many in the material plane have barely seen. Of course, behemoths are loathe to let anyone close to them, let alone allow a humanoid to crawl along their fur...