Krell was a Zotar, a special kind of Demonic Bounty Hunter. He was hired to hunt Belthazor after he betrayed and vanquished the Triad. He worked with Piper and Prue Halliwell to get to Belthazor, who they later discover to be Cole Turner. However, Krell was vanquished by Cole instead when Krell tried to kill Phoebe who had got in the way.