In Assassin's Creed Valhalla, the Daughters of Lerion are super powerful bosses. They also count as Mysteries. The Daughters of Lerion are cultists who take pleasure in death and decay. They are powerful witches with the ability to confuse and disorient the player.
Defeating them will allow you to unlock Thor's Helmet and its attached achievement or trophy, depending on the platform you are playing the game. Each daughter drops an item that is used later on in acquiring Thor's Helmet.
Brief History
The Daughters of Lerion were the daughters of the mythical Briton King Lerion. They are Goneril, Regan and Cordelia. Lenior is also known as King Leir in the pseudohistorical accounts of Geoffrey of Monmouth History of the Kings of Britain.
King Leir was supposed to have ended the male line of Brutus of Troy as he sired three daughters: Goneril, Regan, and Cordelia. As he was dying, he divided his kingdom among his daughters.
The story of King Leir was made famous further by Shakespeare adapting King Leir's story into a tragedy, King Lear. The First Daughter of Lerion: Goneril Fighting Goneril in a mist of poisonous clouds
Goneril can be found in Spalda Fens in Grantebrdigescire. She is in a large arena in a decaying swamp in northeastern Grantebrdigescire. It is highly recommended that you are at least Power Level 90 before fighting her. She is a step up from any of the story bosses you have will have faced at that point, including the non-story bosses like the Zealots.
