Tempus

Tempus was a powerful demon from The charmed series, also called Devil's Sorcerer. He answered directly to The source of all evil.

The story
Tempus was only appeared in episode Déjà Vu All Over Again, in 1999. He was sent by The source to help the demon, inspector Rodriguez. Every time Inspector Rodriguez was defeated, Tempus, thanks to his chronokinetic power, reset time and Rodriguez was ressurected again and again. But the sisters figured out what had been happening, they cast spell to accelerate the time and Tempus was defeated, but not killed. In 2001, in the episode All Hell Breaks Loose, Tempus was asked to reset time by The source, to get time before the Shax attack. Of course it was only trick how to destroy the sisters.