Arwen is a fictional female Elf princess in the Lord of the Rings series. The character was portrayed on screen by Liv Tyler. Her allegiance / loyalty is to the Fellowship of the Ring. Arwen is a Elf princess who helps the Fellowship of the Ring get their objective done. Arwen's nickname is Evenstar but is mainly referred to as Arwen. Her most well known involvement is when Arwen takes the dying Frodo Baggins to Isendur to get treatment. Her powers also extends to being able to call forth a flood that will destroy the Ringwraiths that are following the Fellowship. In the books, it is her father who utters the words that causes the flood to stop the Ringwraiths. Once Lord Sauron has been defeated at the end of LOTR - Return of the King, Arwen marries Aragorn.
Arwen's father is Lord Elrond, one of the most senior Elves in the Middle-Earth trilogy. Arwen's grandmother is Galadriel, another key Elven character in the story.