 Sheppard is known for playing the demon/King of Hell Crowley on "Supernatural" and for his recurring roles as lawyer Romo Lampkin on the "Battlestar Galactica" reboot, Interpol investigator James Sterling on "Leverage", and small-time crime lord Badger on Joss Whedon's "Firefly".At 15, he became a professional musician and enjoyed many years as a recording and touring artist with bands including Robyn Hitchcock, the Television Personalities and the Irish group Light a Big Fire.Mark played drums on Light a Big Fire's second album.