Cymbrel was born of Silwen (an elf) and Berond (half elf). Before Cymbrel was born Berond’s brother, Bergol, made him promise that (if the baby was a girl) Berond would give the baby to him, and Bergol would become the baby’s guardian for life. Berond made this promise unbeknownst to his wife, and when the Cymbrel was born he could not find the heart to tell her, so he knew he must run from the wrath of his brother. Berond told Silwen that their life was in danger, and that the must flee from Mirkwood. The evening of their flight, a man named Nolador received a note from Berond stating that he and Silwen were in mortal danger, and that Nolador must remember, and play his part near the river. The next day Nolador found, next to the river, Berond and Silwen’s child.
From that day on Nolador was to Cymbrel as a father is to his daughter. Before he died, Nolador told Cymbrel all that he knew, and begged of her to avenge her parent’s deaths. Cymbrel was faithful to her promise. (I leave out the details of the story so that they can be developed.)