Lord of Darkness
The Lord of Darkness was a demon sorcerer who once ruled the world before the existence of light. Vampire-like, the Lord of Darkness could not survive in sunlight, and so was forced to flee into the sanctuary of his manor, the Great Tree, when goodness and light first entered the world. He then waited hundreds, perhaps thousands of years for his chance to reclaim his lost title of ruler of the world. He got his chance when he received news that the world's only remaining unicorns had entered his domain. As unicorns' souls harbor the power of light, the Lord of Darkness sent his goblin minions Blix, Pox, and Blunder to hunt them down and slay them.
The goblins succeeded in killing the stallion and cutting off its alicorn, which they presented to Darkness (but not before they'd had their fun with its magic powers), and then captured the mare along with Princess Lily, with whom Darkness was instantly smitten. Taking the advice of his father, he attempted to woo the young Princess, and thought he'd succeeded when Lily asked him to let her be the one to kill the mare, which was by this point locked in the dungeons of the Great Tree. Filled with fiendish pride, Darkness agreed.
However, it was all a trick to allow Lily to get close enough to cut the mare's bonds and set her free. At this point, a small band of adventurers led by Lily's true love Jack and Honeythorn Gump had gained entrance to the Great Tree, and Jack ended up involved in a fight to the death with Darkness, a fight won thanks to the power of sunlight reflected deep into the bowels of the manor by a network of reflective shields set up by Jack and Gump's comrades. Overpowered by the light, the Lord of Darkness was blasted backwards into the Void. He has not been seen since and it assumed he was destroyed for good, although his last words were to the effect that good cannot survive without evil, nor can light without Darkness, meaning he must endure to maintain the balance, and thusly, the Dark Lord is surely alive and well, plotting his revenge against Jack.
