Marnal

The Master had a father.

As children, the First Doctor and Master would play in the fields near the Master's father's estates, with pastures of red grass near Mount Perdition. (TV: The End of Time)

The Master was often discontented and angry. He used to blame his mother and father for it. (AUDIO: I Am The Master)

Behind the scenes

 * In The Gallifrey Chronicles, the Time Lord Marnal mentions he was briefly visited by his son while on Earth in the 1970s, heavily implying that his son is the Master. Indeed, in author Lance Parkin's AHistory, he says the visit of Marnal's son is set during UNIT's hunt for the Master in the television story Colony in Space.