Peter Watts is perhaps the most mysterious character in the series. Like Frank, Peter is an ex-FBI agent. He was the person responsible for bring Frank into the Millennium Group. Although he is a man of few words, it is obvious that Peter is well respected being the "coordinator" of the group.
Terry O'Quinn has numerous stage, screen, and television credits to his name including "Primal Fear", "Young Guns", and "Tombstone". He has appeared in "The X-Files", "LA Law", "Diagnosis Murder", "Alias", "The West Wing", and currently stars in ABC's "LOST".