The Doctors relationship with the Master is a long and intriguing one. The character was introduced in 1971 and recurred throughout the series in various incarnations. Is she a past love? Certainly there is a strong emotional connection between the two Time Lords. While the Doctor in his way sometimes cares too much the Master doesnt care at all. She is what the Doctor might become without the modulating voice of his companions. Peter Capaldis Doctor and Michelle Gomezs Missy share an undeniable yet uncomfortable kind of chemistry. Their awkward attraction to each other is brilliantly played and fascinating to watch. Theres a whole different dynamic when the Doctor is matched with a monster who is his intellectual equal. It increases the stakes and heightens the tension of every scene. The Doctor may no longer be the smartest person in the room.