Amarthiel (Sindarin for Daughter of Doom) was known for many years as the Champion of Angmar. She was instrumental in the fall of Fornost, leading the Witch-king's armies against the city. The defeat of more than one of the garrisons in and around Fornost are credited to Amarthiel and her ring, Narchuil, that bewitched many who looked upon her. Amarthiel was defeated during the Battle of Fornost by Laerdan, an elf of Lindon, and remained hidden from Angmar for many years.
Though she revealed her return in full only recently, Amarthiel has been known to take several disguises, perhaps most notably that of Sara Oakheart, and later that of the Lossoth wise-woman, Saija, to spy on one of her Black Númenórean lieutenants, Mordrambor, who she suspected of treachery. Her final appearance as Amarthiel comes at the old Ring-forges of Eregion, at Tham Mírdain.
Amarthiel appears in the following Epic quest instances and locations; at some occasions she engages in combat:
-  Volume I, Book 9, Instance: Oakheart's Might — Barad Gúlaran in Angmar
-  Volume I, Book 9, Instance: Amarthiel's Hope — Annúminas in Evendim
-  Volume I, Book 10, Instance: The Eye of Angmar — Barad Tironn in Evendim
-  Volume I, Book 13, Instance: The Path of Aearil — Halla-kolo in Forochel
-  Volume I, Book 14, Instance: The Prisoner of Sammath Baul (Session Play) — Sammath Baul in Angmar
-  Volume I, Book 14, Instance: The Fate of Laerdan (Session Play) — Tham Mírdain in Eregion
-  Volume I, Book 14, Instance: The Doom of the North — Tham Mírdain in Eregion
- Amarthiel was once known as Narmeleth, a talented ring-smith corrupted by her own ring's power. She was later defeated by Mordirith, then Mordrambor cut off her hand and stole Narchuil. This weakened Amarthiel to the point that Narmeleth was able to overcome her influence forever.
- A post by MadeOfLions on 15 January 2015 about Amarthiel:
Amarthiel is indeed exclusive to LOTRO - you won't find her in Tolkien's works, though the inspiration for her comes from here and there throughout. We had lengthy meetings back in the day to work out her story and bring her to life, names you'd probably recognize if you've been here since the beginning: Keth, NobOrBob, Berephon, and myself on the story side, and Floon with the art. Amlug even contributed a crucial book of the Epic (Volume I, Book 9 - which gave us some particularly flashy Amarthiel moments). I wouldn't say we pulled her out of a magic hat, though. The themes that revolve around Amarthiel are very much in tune with Lord of the Rings, I think. MoL