The Return of the King
In 'The Return of the King' movie, Elrond finally accepts Arwen's choice to stay in Middle-earth. In the world of the film, Arwen's life begins to fade, and we learn that she will die soon if Sauron is not defeated. In response to her plea, Elrond orders Narsil to be reforged and bears the sword, newly-reforged as Andúril, to Aragorn. The film emphasises Elrond's concern for Arwen as the motivation for his decision to intervene to aid Aragorn, and he announces that it is "on her behalf" that he travels. At the same time this results in a more positive role for Elrond that seems closer to his characterisation in the books. Elrond urges Aragorn to take up his destiny, and tells him that he has the power to command the armies of the dead that dwell under the mountain. In the book Aragorn already has the sword, and it is Elrond's sons who travel to Aragorn, bearing a message from Elrond about the Paths of the Dead. Incidentally, although there are no elves at Helm's Deep in the books, in 'The Return of the King' Elladan and Elrohir do accompany Aragorn through the Paths of the Dead to the Pelennor Fields, and to the final battle at the Black Gate.
As in the books, Elrond brings Arwen to Minas Tirith for her marriage to Aragorn, the coronation scene beautifully suggesting both his joy and his pain at this final outcome. The film omits Elrond's return journey to Rivendell, with Gandalf and the Hobbits, where he gives them hospitality once more. In the films Rivendell is portrayed as rather bleak and empty after 'The Fellowship of the Ring', and it seems that most of the elves have already left. In the books, however, Rivendell is still full of 'light and song', and the elves rejoice at Elrond's return.
The last we see of Elrond in the movies, as in the books, is at the Grey Havens, preparing to sail from Middle-earth. His final words ("I Aear cân ven na mar" - "the sea calls us home") suggest the joy of the fulfilment of his task in Middle-earth and his final homecoming.