An old friend, and an old foe, The Master has faced the Doctor throughout several lifecycles. They have been reborn after seemingly dying for good (more than once) and changed far beyond the mustachioed origins of Roger Delgado, to the enigmatic psychopathy of Michelle Gomez. He (or she, depending on the regeneration) is very much the Moriarty to the Doctor's Sherlock Holmes. For all the horrific aliens and monsters that he faces, the Doctor's greatest foe will always be his twisted Time Lord counterpart. Legendary actor Derek Jacobi even portrayed Professor Yana, The Master’s humanized personality, and the performance was as electric as the exposed cables with which he murdered Chantho.
