Elrond is the father of Arwen in J.R.R. Tolkien’s legendarium.
Elrond is a Half-elven lord who rules Rivendell during the events of The Hobbit and The Lord of the Rings. He is the son of Eärendil and Elwing and the twin brother of Elros, who became the first king of Númenor.
Elrond has three children with Celebrían: the twins Elladan and Elrohir, and Arwen. Arwen is called Undómiel, or Evenstar, and eventually chooses a mortal life so that she can marry Aragorn.
Celeborn is Arwen’s grandfather through her mother, not her father. Elrond’s brother Elros is also sometimes confused with her parentage, but he belongs to an earlier generation and founded the royal line of Númenor.