In a tale featuring the bigger-than-life evil of Sauron and Saruman, a human-scale villain might seem like a secondary threat. But the cunning of Grima Wormtongue looms large across Middle-earth. From the halls of Edoras to the pinnacle of Isengard, he spins a destructive web of deceit and betrayal.

It takes an actor of particular experience to deliver in such a demanding role, which makes Brad Dourif an ideal fit. His career began with an Oscar®-nominated performance in One Flew Over the Cuckoo's Nest, and has included Blue Velvet, The Exorcist III and even the voice of Chucky in the Child's Play films. It's almost as if Dourif had been groomed all along for Grima, the corrupted advisor to King Theoden and servant of Saruman.

Can you explain how Grima fits into the big picture of evil in Middle-earth?
Saruman wants to destroy mankind, and his first step is to destroy the Rohan calvary. To do that, he needs to turn Wormtongue, the Rohan king's advisor, against the king and against the kingdom.

It's an unusual character for Tolkein, in that he works against his own race.
He's the only human I can remember in the story that is turned to work for evil, to work to the death of mankind. Therefore, you have to do your job in telling the story and my focus was how do I make people see that he's a human being.

How did you go about doing that?
First, I sat down with [writers] Fran Walsh and Phillipa Boyens and we went over what we could do with Grima. The problem with adapting this literary piece to a movie is that Tolkien's strength is in description, not in dialogue. So whereas you could take somebody like Dickens, who's a genius with dialogue and you can tell who his people are by the way they talk, you can't do that as much with Tolkien.

So where did you discover your inspiration for the role?
We decided that Grima is ugly, that he was picked on and in being picked on he learned to be really good at reading human behavior. Because if you want to avoid the cruelty in people, you do that by thinking ahead-why is a person thinking this, how are they going to react to that. Reading people will get you out of trouble. So he learned to be very, very good at it. He's a very sharp guy, a lot of innate talent, a very lucid clear thinker.

And that makes him suited to be a confidant to King Theoden?
That's exactly what the King needs in an advisor, somebody who's going to figure out what people are going to do and when. What's the smart thing to do here based on what other people are going to do? If anybody's going to know the answers to those questions, it's going to be Grima. On the other hand, because he's ugly in the way he feels about himself, he's very involved in this family, but doesn't belong. So the thing he needs in terms of love, he never can get.

You said you envisioned Grima as always being picked on. Who do you conceive as his bully?
The bully becomes everyone who doesn't accept him. The bully was somebody in school who may or may not have been a member of the King's family, or several people. Something of his own making. He just set himself up.

What was it like working with Christopher Lee on the Isengard scenes?
Great. What a storyteller. What a fun guy. Christopher's been around forever, knows every single person on planet Earth and has done everything. There's just no end to stuff he can tell you. He was the only one on set who actually knew Tolkien and he knew the text better than anybody.

What was your impression of Edoras? That was reportedly a spectacular location.
Edoras was beautiful. It was like a piece of Middle-earth time-warped here. You're looking out on this high hill, this pure medieval world. Medieval costumes, swords and everything. It was truly remote, with expanse and specificity of time and place. Probably very few people on earth will get to go to that place. That's time travel.

Was there any particular moment from filming that has stuck with you more than any other?
I did a scene with Miranda Otto [as Eowyn] in a studio-really a shed with a corrugated metal roof-and the wind was blowing and the thing was rattling and it sounded like a King Lear play where they rattle the metal to make thunder and lightning. It was so loud that at one point I had to stop and say "Guys, I can't hear." And Miranda didn't even notice the noise, that's how into the scene she was. I thought that was remarkable. This girl must be a genius to be so involved in what she's doing that she doesn't even notice she can't hear the other actor.