During the War of the Ring, Berembor was among the elves who accompanied Haldir of Lorien to Helm's Deep, a large valley in the north-western Ered Nimrais. There, they aided King Theoden and his people in defending the keep from an army of 10,000 Uruk-hai that were dispatched by Saruman to destroy the people of Rohan. Stationed at the Deeping Wall, she was seen between Erethón and Celebrílad when Aragorn walked pass them, informing all elves to show no mercy to the Uruk-hai that were preparing to charge. As the Uruk-hai were charging towards the fortress, including the Deeping Wall, Berembor and the elves loaded their bows and demonstrated their unmatched proficiency of archery, as they loosened devastating hails of arrows in seconds, killing many Uruk-hai. She was eventually killed during the Battle of the Hornburg.