El Rey is a ruthless man with a tragic story behind him. A story of how a once benevolent man was corrupted with power, and stole all the magic of Nowhere for himself (Season 1, Episode 06; "El Rey").
Once upon a time, when El Rey was a young heroic swordsman, he approached a magical tower guarded by many obstacles: skeletons, mechanical traps, flesh-eating thorns and archers. When he reached the top, he found a magic crown and with its power, he became the ruler of Nowhere.
For many years, El Rey used the magic of the crown to help his people. Then one day, weakened by old age, he discovered his magic has stopped working. He sought the council of another magic user, an old sage, to see if anything could be done. With the power of a spell, his crown devoured the man El Rey sought council from, restoring his youth and power, but also irreversibly corrupting him.
Afterwards, El Rey started stealing magic from his subjects one by one, until there was almost no magic users left. When the people rioted against him, with the power of stolen magic, El Rey turned four of his minions into creatures of magic to help him conquer back the kingdom. They defeated El Rey's enemies, burned cities to the ground, and established El Rey's iron rule once more, each guarding one corner of the land.
The last person in Nowhere with magic was the Nomad, and El Rey made him the most wanted man in his kingdom, waiting for the day when bounty hunters would bring him before the king, so he could steal the last drops of free magic in the land.