The Master (Exile)
The Master is a Time Lord (Exile).
The Master has used many fake names, including Roger, Peter, Geoffrey, Tony, Eric, Robert and Sam.(Exile (audio story))
Behind the scenes
Roger, Peter, Geoffrey, Tony, Eric, Robert and Sam all refer to the actors that played the Master, like Roger Delgado, Peter Pratt, Geoffrey Beevers, Anthony Ainley, Eric Roberts, and Sam Kisgart.