Nimyrniel was born on December 28th in the year 1593 of the Second Age. Her birth in the Elvish city of Gwingris came in a time of great snowfall, and for this she was named Nimyrniel, meaning "Lady of White Trees". As a child in Eregion, Nimyrniel was too young to understand the dread which fell upon her kin when Annatar left their lands and proclaimed himself as Sauron. Shortly after her coming of age, the forces of Sauron came upon Eregion and ravaged the Elven lands, and her family fled northwards with haste. With many others led by Elrond Half-Elven, her family took up residence in the refuge of Imladris at the feet of the Misty Mountains, where they remained for the rest of their days.

In Imladris, Nimyrniel took it upon herself to study the history and lore of the dreadful times that she did not understand in her youth. Desiring to preserve the knowledge of the Eldar against those who would see it undone as it had been in Eregion, Nimyrniel continued her studies into the most ancient of Elvish and Mannish lore.

To this day, Nimyrniel's studies continue as the histories of Men continue to be written and rediscovered. She has spent a particular amount of time into studying the lands of Eriador, which she journeys often as she aids her kin in their departure westwards to the Grey Havens, a journey which she too shall make when she believes her studies have come to their end. Though, with the Age of Men approaching and further histories to be written with them, she is uncertain of when this day will come.