The Master: Have a care, Doctor! I have the power of life and death over you!
The Doctor catches a glimpse of a body lying in the rubble. He rushes towards it. It's a woman, her clothes dirty, torn and streaked with blood. It's Jasmine Tate.
The Master: No! NO! NOOOOOOOOOO!
Then from the smoldering dust covered cloak, a tiny spark of energy floats up. The Doctor tenses up for what’s going to happen next. He watches as the spark wafts into the air and floats across the rubble to where the still form of Jasmine Tate lies. The spark gently touches her forehead. The instant the spark vanishes, Jasmine’s body spasms briefly and she begins to breathe.
Ah, you picked up on my subtle clues. He is a renegade Time Lord who appeared on Doctor Who twice during the 1st Doctor's time but has not been seen on screen since. (However he has made appearance in various expanded universe stories.)