Also known as エルフェンリート, Elfen Song or Elfic Song.
This TV series has 13 episodes with each episode lasts for about 25 min. Its original run was from July 25, 2004 to October 17, 2004.
Elfen Lied’s genres are action, horror, psychological, romance and supernatural. Since it contains mild nudity, it is rated R+.
Here is one of the Elfen Lied videos I found and like: