Morgause's Fortress

"If we weren't sure Morgause was a sorcerer before, we can be certain of it now."

- Merlin to Arthur

Morgause's Fortress is a castle located in Odin's Kingdom. It can be accessed through a hidden tunnel behind a waterfall. It was formerly occupied by the High Priestess Morgause.

History
Before she departed from Camelot, Morgause placed an enchantment on Arthur's horse that showed it the way to her fortress. The horse led Arthur and Merlin to a lake in a forested area of Odin's Kingdom. The lake was fed by a waterfall, behind which was a hidden tunnel that led to Morgause's home.

Morgause led them to a courtyard, where she challenged Arthur to place his head on a chopping block. When he kept his promise and did as she asked, Morgause rewarded Arthur's courage and honesty by using her magic to summon his mother's spirit. Their encounter led Arthur to discover the truth about his birth, after which he and Merlin returned to Camelot (The Sins of the Father).