The Master and the Doctor are contemporaries, rival Time Lords from their student days at the Academy on Gallifrey. Although the Master is also a renegade, he is dedicated to creating chaos and destruction throughout the universe, sometimes just for the fun of it. At the same time he seeks power over others. Once friends, the Doctor and he are now the bitterest of enemies: the Master is determined to kill the Doctor and lays deadly traps through space and time to attain this objective.

No trick is too low for the cunning Master. He will threaten and endanger the lives of innocents and enlist the help of the most dangerous aliens in the universe if he believes it will give him power. The Master has even resorted to working with the Daleks. He is an ally of dubious worth, however, as he is always out for his own good, and will betray his allies if it is expedient to do so.

Charm and subtlety are the two main weapons of the Master. He is devilishly charismatic, disarmingly polite and well-dressed, enabling him to sway people to his way of thinking by simple argument and strength of personality. If gentle persuasion does not work, he uses hypnotism; if that fails he resorts to anger, threats and abuse. It is in failure that the Master's megalomaniac personality comes forth, although he is quick to suppress any outbursts of temper.

The Master's plans, however, are seldom straightforward. He uses a devious selection of traps to snare the unwary or to ensure he has time to escape when his plans go wrong. His quest for power leads him to investigate powerful civilizations in attempts to learn their secrets. The Master will use the superstitions and beliefs of a people against them while manipulating their technology. Yet he sometimes underestimates both the resolve of the people and the power of their technology, ending up with nothing.

He is a formidable expert at disguise, using many means from rubber masks and thaetrical make-up to advanced holography methods to hide his true appearance and deceive his enemies.

Unlike the Doctor, the Master no longer has the power of regeneration because he has reached the end of his natural life cycle. By force of will and hatred for the Time Lords and the Doctor, however, the Master kept his decaying thirteenth incarnation alive long enough to absorb body of Consul Tremas of Traken, whose form he adopted until the Daleks sentenced him to extermination.

The Master's hate filled essence refused to depart this plane and he escaped to Earth in the year 1999 where he took over the body a paramedic named Bruce. But this time the merge wasn't successful and body rapidly began to decay and die. He attempted to take the Doctor's body but was thwarted and appeared to be absorbed into the Eye of Harmony. It is unkown if the Master survived.

The Master has dark, short swept-back hair, a pointed beard and moustache, and blue eyes and dark, brooding eyebrows. He wears a simple black jacket and trousers, with an ornate collar that is embroidered with silver in a diamond pattern. He wears black gloves.