The Chernabog, also known as the Demon, is a minor antagonist in Season 4 of ABC's Once Upon a Time. He seeks out to destroy the soul with the greatest potential for darkness and guarded the dark curse. It once encountered Maleficent Cruella deville and Ursula the sea witch after being touched by Rumpelstiltskin to retrieve the curse from Bald Mountain. However the three witches got away from the creature after reluctantly relying on one another to get out of the cave. After being trapped in the sorcerer's hat the demon was set loose on storybrook, beginning to hunt down Emma Swan, who had a far greater potential for Darkness than Regina did.
It continued to chase after Emma and Regina however, it was ultimately destroyed when the two women worked together and sent it across the Town Line into a world without magic, ultimately eliminating it.