Scáthach

Scáthach, also known as the Witch of the Woods, is the main antagonist of American Horror Story: Roanoke. A powerful witch serving an ancient, evil religion predating Christianity, Scáthach's corrupting influence is directly responsible for several colonial incidents, most notably the disappearance of the Roanoke colony. Chronologically, she is the first Supreme Witch.

In the re-enactment scenes of My Roanoke Nightmare, she is portrayed by singer Lady Gaga, who also portrayed the Countess Elizabeth Johnson. She is primarily portrayed by actress Alexandra Daddario.

Background
Scáthach was once an English woman who was descended from both druids and their Roman conquerors. A worshiper of old pagan gods, she left for the British colonies as a stowaway on a voyage that was plagued with death. Upon being discovered at landfall, the British soldiers blamed Scáthach's female presence for enraging the sea gods, imprisoned her and sentenced her to be burned at the stake. She answered the call of more ancient and bloodthirsty gods and massacred the soldiers, thereby incriminating the Native Americans and allowing her to escape into the wild.

In the 1500s, Scáthach came across the exiled former leader of the Roanoke colony, Tomasyn White, who she spared from a wild boar, in exchange for her soul. After White returned to Roanoke and violently regained control of the colony, the colonists were subjugated to follow in Scáthach's religious ways. The colony migrated to a location in North Carolina, hundreds of miles away. White's own son, Ambrose, defied his mother and called on the colonists to return to Christ. As such, White personally killed the entire colony, so that their souls would belong to Scáthach. As a final component of the deal, White let Scáthach take her life, for eternal posthumous servitude.

Over the hundreds of years since, many encountered Scáthach and her ghostly Roanoke followers. While most would die under White's blade, Scáthach had a strong sexual appetite that she loved to have sated by hapless men.

Recent History
Matt Miller, the new owner of the colonial mansion located on Scáthach's domain, attracted the witch's attention. At the first opportunity, she bewitched Miller and engaged in an orgy with Matt, much to the chagrin of his wife, Shelby. It was at this point that the clairvoyant Cricket discovered Scáthach's identity as the true architect of the land's corruption. The next evening, she lured Matt out to the cellar, where she once again seduced him, but also shared her life's story with him.

The survivors of the Roanoke incident, as well as the actors from My Roanoke Nightmare, return to the mansion. Scáthach summons Matt to the basement of the house, where they once again engage in a passionate embrace. Shelby and Dominic Banks interrupt, prompting Matt to confess that he returned to the house to be with his one true love- Scáthach. Subsequently, Shelby murders him in a rage.

During the final night of the blood moon, Scáthach saves the grievously wounded Lee Harris by slaughtering a wild boar sniffing her out. Scáthach cuts out the boar's heart and offers it to Lee, who consumes it for salvation, in exchange for her soul. Under Scáthach's control, Lee sees to the death of every living person on the mansion's property, alongside Tomasyn White and the Roanoke colony.

Trivia

 * She was named after the in the Ulster Cycle of Irish mythology.
 * American Horror Story co-creator Ryan Murphy revealed to The Huffington Post that Scáthach was the first Supreme Witch.