Miraak

 is the primary antagonist in. According to himself, the locals of Solstheim, and Hermaeus Mora, he is the first Dragonborn. He was also one of the Dragon Priests. His name, in the dragon language, means "Allegiance Guide".

Background
During the period of time when dragons ruled over mortals, Miraak served as a dragon priest on the island of Solstheim. At some point before his death, he turned on his dragon masters, using his power to devour the souls of dragons to feed on their power. Around this same time, he came into the service of Hermaeus Mora, the Daedric Lord of Knowledge and Fate, who taught him a means to great power. After his death, he lived on in Apocrypha, the realm of Hermaeus Mora, until the time was right for his return.

Dragonborn
Shortly after the quest The Horn of Jurgen Windcaller, two Cultist Adepts will approach the player, in any of the main cities, asking if he or she is the Dragonborn. They will then commence an attack on the player, attempting to kill them. Upon their death, the Dragonborn will find a note with orders to kill the "False" Dragonborn in order to please Miraak.

Trivia

 * During the main quest of, should the Dragonborn kill a dragon while on Solstheim, Miraak will appear and steal the soul of the dragon from the Dragonborn.