Suggestions by @marvin

Mads Mikkelsen

as Lord Vetinari in Discworld

Sherlock Holmes (Character)

as Lord Vetinari in Discworld

Richard Dormer

as Sam Vimes in Discworld

Henry Cavill

as Mandorallen in The Belgariad

Rosamund Pike

as Pol in The Belgariad

Sylvester McCoy

as Wolf in The Belgariad

Lee Pace

as Lord Voldemort in Harry Potter (HBO Max Series)

Daisy Ridley

as Jasmine in Deltora Quest

Thomas Jane

as Samuel Vimes in Discworld

Tom Hopper

as Captain Carrot in Discworld

Thomas Jane

as Sam Vimes in Discworld

Tom Hopper

as Carrot Ironfoundersson in Discworld

Thomas Jane

as Sam Vimes in The Watch

Eva Green

as China Sorrows in Skulduggery Pleasant

Peter Capaldi

as Mogget in The Old Kingdom

Ralph Fiennes

as Lord Vetinari in The Watch

Jeremy Irons

as Lord Vetinari in The Watch

Katie McGrath

as Sabriel in The Old Kingdom