1. An innocent-looking exterior

-His question-mark umbrella, colourful jumpers and playful manner make him appear harmless.
-Often uses jokes, riddles and apparent foolishness to conceal his true intentions.
-Encourages others to underestimate him, giving him an advantage before they realise what he is doing.

2. A master strategist

-Thinks several steps ahead, anticipating how people and events will develop.
-Often constructs elaborate plans in which seemingly unrelated events serve a greater purpose.
-In Remembrance of the Daleks (1988), he manipulates the conflict between rival Dalek factions while pursuing his own objectives involving the Hand of Omega.

3. A manipulator of people

-Understands the fears, ambitions and weaknesses of those around him.
-Sometimes withholds information from his companions because he believes they must play a particular part in his plans.
-His relationship with Ace reveals the complicated consequences of guiding someone else's development without always explaining his intentions.

4. A willingness to play dangerous games

-Is prepared to deceive powerful enemies and take calculated risks to prevent greater catastrophes.
-Can appear cold or ruthless when pursuing what he believes is the necessary outcome.
-In The Curse of Fenric (1989), he confronts an ancient adversary through a complex contest of intelligence, deception and psychological manipulation.

5. A darker, morally complex hero

-His methods raise questions about whether good intentions justify manipulating others.
-Often carries the burden of knowing more than he can safely reveal.
-Unlike the more openly compassionate Doctors, he sometimes protects people by keeping them in the dark, making his victories as unsettling as they are impressive.