The Master

A renegade Time Lord and archenemy of the Doctor.
Here's a list of all the classic episodes he appeared in...
Terror Of
The Autons
The deadly plastic
aliens return. This
time as daffodils.
The Claws Of Axos
The Axons promise
Earth a golden age
of prosperity and big
frogs.
The Daemons
The Master raises
the Devil. The
Doctor becomes
a wizard.
The Time Monster
Atlantis is at stake
when the Master
summons a
Chronovore.
The Deadly
Assassin
Did the Doctor just
assasinate the Time
Lord President?
Logopolis
The Universe is
falling apart.
Time-Flight
The Master plans to
free an alien race
by kidnapping
Concorde.
The Five Doctors
The Doctors must
play games in a
Gallifreyan
amusement park.
The Mark of
the Rani
The Doctor puts a
Rocket up the
Rani's plans.
Survival
A visit to the suburbs lands the Doctor and Ace on a planet of killer cats.
The Mind of Evil
Can the Keller Machine really cure all crime?
Colony In Space
An alien quarry hides the most powerful weapon in the universe.
The Sea Devils
A race of underwater reptiles start to attack shipping.
Frontier In Space
What sinister force has the humans and Draconians at war?
The Keeper of Traken
A living statue poses a deadly threat.
Castrovalva
Is Castrovalva a sanctuary, or a trap?
The King's Demons
The Doctor finds a robot on the English throne.
Planet of Fire
What connects Lanzarote to the suspiciously similar planet of Sarn?
The Trial of a Timelord: The Ultimate Foe
The Doctor must fight for his lives.
The TV Movie
A new Doctor wanders San Francisco before the world ends.