Well it was just one episode.
If you watched Charmed, you saw him before.
You just probably won't know it's him until you re-watch it... and then you'll be like. Oh I remember him in this episode. lol He was evil, and you saw him quite a lot.
It was episode
4x03: Enter the Demon.
On Angel, minor role but you see him quite awhile.
He works for the bad company. lol kind of like with LOST.
On 24, he's one of my favorite although he had a minor role.
He was in S2-S3.