Perhaps you saw his iconic turn as “Theodore ‘T-Bag’ Bagwell” on the now-defunct FOX network series Prison Break.  Or more recently, you may have seen him as the somewhat misunderstood yet always villianous “Samuel Sullivan” in the final season of NBC’s genre series Heroes.

But if you’ve never seen him before, make no mistake:  Robert Knepper is a character actor to be reckoned with.

Knepper makes his Stargate franchise acting debut as Lucian Alliance member “Simeon” in tomorrow’s premiere of Season Two of Stargate Universe — airing at 9 PM Eastern (8PM Central) on SyFy.  The episode, entitled “Intervention,” marks the first of several episodes featuring the actor in a recurring role.

GateWorld recently spoke with several members of SGU‘s regular cast, and all of them praised Knepper for his work on the series thus far.

Brian J. Smith (“Lt. Matthew Scott”) summed up in one word the dynamic Knepper brings with his character.

“Menace.  He brings menace,” Smith said. “The whole Lucian Alliance storyline is really great, because it brings in this external force that forces everyone on the ship to band together.  And to come together as a team.”

“While alot of the first season was about the uneasy relationship between civilians and military and the different agendas on the ship, I think Season Two is about how they find unity when they are forced to,” Smith continued.  “And sometimes when you’re forced, you have to ask ‘Is it genuine?  Is it a real attempt at common ground?’  Or was the unity just an immediate need, and is it dissolvable?”

Elyse Levesque (“Chloe Armstrong”) echoed Smith’s statements in more detail.

“[He’s a] scary twisted man!”  Levesque joked. “Robert Knepper is famous for playing these really dark, twisted — you could say insane — characters.  He’s outdone himself here on SGU.  He doesn’t want peace.  He’s an instigator.  He’s a troublemaker.  He wants to push the boundaries and see how far he can go before he gets pushed back.”

“He’s a loose cannon, and nobody knows what he’s going to do.  So it’s an interesting dynamic,”  Levesque said.

Perhaps the best reviews of Knepper’s performance are offered up by Louis Ferreira (“Colonel Young”) — who talked about Knepper in our exclusive interview with him. (interview)

“He’s an amazing actor!” Ferreira said. “He — very well, I might add — represents the threat of the Lucian Alliance to someone like Colonel Young, whose trying to protect his own people.  He embodies that threat.  It’s like watching a good guest spot and going ‘That villian was unbelievable!’  He just keeps bringing you back to watch.”

Keep your browser to GateWorld for more SGU news and beyond throughout this premiere week!