Niënor also called Niënor Níniel “Tear-Maiden”, was Húrin and Morwen’s third child, the sister of Túrin Turambar.
As a child, her mother escaped from Dor-lómin to Doriath, where she was brought up at the court of King Thingol. As a young girl she went along with group of Elves, on the lookout for her brother to Nargothrond, where she found only dragon Glaurung, who threw a spell on her, resulting in lost memory. In confusion and terror, Nienor ran away, tore off her clothes and ran naked through the forest until she fainted. Her brother Túrin found her, naked and terrified, at Haudh-en-Elleth, lying on the grave of his dead lover Finduilas. Because Nienor did not remember her identity and Túrin did not know his sister, as he had never seen her before, he named her Níniel which means “Tear-Maiden”, and brought her to safety at Brethil where eventually they got married. By the next spring, she was halfway through her first pregnancy.
Shortly afterwards, when Túrin went in search of Glaurung, Niënor followed him. When Túrin was struck with venom and lay unconscious after the fight with the dragon , Niënor learned from the dying Glaurung that Turambar is her brother.
Realising she had married her own brother and was carrying his unborn child, she committed suicide by throwing herself into the ravine at Cabed-en-Aras. Her death sparked a series of events culminating in his suicide, thus fulfilling Glaurung’s vengeance.