The actor told Collider that there is a "duality" to his role as the famous wizard.
"I think [his allegiance] is up for interpretation," he claimed. "Essentially, he's for the good, but he fights fire with fire. He drives out a nail with another nail. He doesn't turn the other cheek."
Fiennes added that his portrayal of the character would be "Machiavellian".
"I don't think Merlin is a villain, but I think he's complex and far from driven snow," he explained. "He's brilliant at getting the people to believe what he thinks they should believe, to coerce them into a vote which carries forward what he wants to happen."
Showrunner Chris Chiball previously revealed that he had planned "multiple seasons" of Camelot.
The series is expected to premiere on Starz in early 2011 and will air on Channel 4 in the UK later in the year.`