Halfrek or Hallie is a recurring fictional character on the TV series Buffy the Vampire Slayer. She appears as a vengeance demon in seasons 6 and 7, and has previously appeared as Cecily in season 5. She is played by actress Kali Rocha.

Kali Rocha is an American actress. She is known for portraying Karen Rooney, the mother of four Rooney children and school's vice principal, in the Disney Channel sitcom Liv and Maddie. She has also co-written four episodes of the show.