Appears in: The Fellowship of the Ring The Two Towers The Return of the King
Elrond In The Return of the King:
After having set out for the Grey Havens, Arwen turns back when she has a vision of Eldarion. When she returns to Rivendell, she questions Elrond about the future. He admits that he did see a child as a possibility, but pleads with her as her father. He does not want her to give up her immortality. However, it's too late because Arwen begins to grow cold as her life begins to slip away as a mortal. She then tells Elrond that it is time.
Elrond travels to Dunharrow where the Rohirrim are gathering. Aragorn is also there. Elrond gives him Narsil, which has been reforged as Andúril at Arwen's request. He tells Aragorn that it is time for him to begin to act as the rightful King of Gondor and that Arwen is now dying. After the quest is successful and the Ring has been destroyed, Aragorn is crowned King and Elrond brings Arwen to Minas Tirith so they can be married.