The Behemoth is an Emblem Heartless, encountered exclusively as a boss in Kingdom Hearts, Kingdom Hearts Final Mix, and Kingdom Hearts Re:coded. They can also be found as a raid boss in Kingdom Hearts Union χ.
The Behemoth is one of the three powerful Heartless released by the Final Keyhole. The other two leave to attack Neverland and Agrabah, while Behemoth remains and guards the Keyhole. Other Behemoths are also found in the Hades Cup and End of the World. These Behemoths were repurposed as the Destroyed and Arc Behemoths in Kingdom Hearts Final Mix.
A Behemoth is a massive, quadrupedal Heartless. Its body is predominantly lilac in color, but its back and all four of its legs are violet. Each of the Behemoth's legs have two toes with black claws. It has two large, curved tusks sprouting from its lower jaw that are white on their upper half and lilac on their lower half. The Behemoth's conical, black horn is on its forehead. Like most other Heartless, it has yellow eyes and a jagged maw. Its Heartless emblem is on its chest.
It is based on Behemoths from the Final Fantasy series; large purple monsters with two bull-like horns and a lion-like body.