Mark Sheppard — English Actor born on May 30, 1964,

Mark Andreas Sheppard is an English, American naturalized, actor and musician, born in London, England of an Irish-German background. He is often credited as "Mark A. Sheppard". Sheppard is best known for his recurring roles as the demon Crowley on Supernatural, 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... (wikipedia)

It's a fascinating job, to come in and be the most interesting person in an episode. Whoever the guest star is, that's the job - to maintain the interest and the focus for that 42 minutes or whatever, and it should be a huge relief to those people that are the leads in the shows.
With sci-fi you get these kind of stories in historical drama, and it's just so fabulous.
It's the imagination that is involved in sci-fi, and fantasy is what draws me to it. Stories, everything.
I can go to a movie theater and watch a movie I was in with an audience... but with television, the opportunity to meet the fans at Comic Con or any other situation, it's a chance to enter that circle; it's that sharing.
When something is written for you or handed to you, sometimes there's a very interesting dance as you discover what it is that's required.