Seventh Doctor

Regeneration - Post-Regeneration
It has been suggested (mostly through journeys through the Doctor's psyche) that his seventh self forced a regeneration in his sixth persona because he was too out of control, and was heading down the road to become the Valeyard. (NA: Timewyrm: Revelation)

Thus when the TARDIS was attacked by the Rani, the Doctor deliberately hit his head on the console, triggering a regeneration and allowing his seventh persona to come into being. Following his regeneration he had a slightly comic personality, due mostly to post-regenerative trauma. (DW: Time and the Rani)

Ace and Facing Fears
When the Doctor and Mel arrived on the planet Svartos the Doctor encountered Ace, a much more brash human and recognised something in her that would assist him in the future as Time's Champion. He used a mild form of hypnosis to persuade his current companion Melanie Bush into leaving him. (NA: Damaged Goods)

The Doctor lead Ace to through many challenges, leading her to face her fears, with the intent that she might take his place in the future.

Time's Champion
The Doctor became the eternal Champion of Time, assisting the universe and Time in the more complicated historical challenges. One such challenge involving the Hoothi was seen by Ace as an ultimate betrayal, leading her to leave his company during events on the planet Heaven. It also led Bernice Summerfield to join him. (NA: Love and War)

Characteristics
The Seventh Doctor was a darker character, manipulative and frequently saw the 'bigger picture' rather than the world before him.

Personality
This incarnation was well-known for being, as the Master said in Destiny of the Doctors as "...one so busy setting plans and traps..."

While the Seventh Doctor would sometimes act like a buffoon, he usually preferred to manipulate events from behind the scenes; much like his second incarnation, he was prepared to play the fool in order to trick his foes into underestimating him, inevitably leading to their defeat at his hands.

Surprisingly, given his appearance and stature, he was actually capable of both directly and indirectly taking control of situations involving strangers, using his greater intelligence to assess and direct events. Although his more obvious whimsical tendencies disappeared over time, he maintained a fondness for idiosyncratic speeches that occasionally referred to literature, ordinary places and even food and drink amidst the weightier concerns on his mind. He was empathetic to his friends (and even his enemies, such as Helen A) and somewhat melancholic at times (such as during Mel's departure and before his decision to eradicate the Daleks) but now placed greater burdens upon himself in the name of protecting the universe. This may have led him to surround his true intentions in mystery and the use of sleight of hand as befit his fondness for performance, in effect, subverting his more lighthearted qualities to complement and enhance his heroic and darker ones. Concerned with the bigger picture, he would sometimes overlook the finer details and his planning, both pre-prepared and improvised, would sometimes have fatal results and consequences. When he acted to end threats, it was usually a ruthless, destructive and final maneuver.

He was also not above hiding the truth from his friends and allies and using them in order to complete his schemes and gambits.

His tendency to reveal only select information to his companion Ace — as well as anyone else around them — was utilised both in her education and in their adventures, as if he were the only one who should know all the answers and others should come to their own conclusions. At two points he even abused Ace's trust in him, once to develop her as a person and again to save her life (on both occasions, freeing her from the evil influences that had haunted her during her life). In spite of his immense fondness for her, and her for him, he often frustrated her with his secretive nature as his alien behaviour, the great importance of his objectives (especially his focus on obliterating enemies from his past) and his strong desire to both educate and protect her would lead him to keep even her in the dark and would even subordinate her feelings towards him in order to succeed in their battles. Fortunately, their close, almost familial bond was likely what helped Ace in moving past the feelings of betrayal she sometimes felt towards the Doctor, particularly as he genuinely had her best interests at heart. In fact, while he appeared to be an unassuming figure, fond of performing magic tricks and displaying notable showmanship, the Seventh Doctor was actually quite powerful and calculating, for he would use his friends and foes alike as pawns in his elaborate chess game against "evil". As Ace herself put it, he was "well devious."

In direct contrast to his third incarnation, this Doctor was absolutely opposed to violence of any sort (as demonstrated in stories such as Battlefield, where he stops a battle merely by ordering the warriors to desist) and he was totally against the use of firearms (to the extent of 'talking down' a soldier ordered to execute him in The Happiness Patrol by emphasising the easiness of the kill versus the enormity of ending a life), although he also proved capable of rendering a man unconscious with a touch. In keeping with his established habits, he would use gadgetry of his own invention when the situation called for it, but never as his final gambit. Instead, he almost always managed to talk his enemies into submission, often into suicide – perhaps most memorably in Remembrance of the Daleks, where he taunts the seemingly last Dalek in existence until it self-destructs, or in Ghost Light, where he defeats the malevolent Light by ramming home the folly of trying to prevent evolution (he employs variations of this 'talk to death' tactic in Dragonfire, Silver Nemesis and The Curse of Fenric, although primarily to manipulate opponents to guarantee the outcome in his favour). Perhaps this Doctor's most definitive stand against violence and savagery was taken when he faced down his arch-foe the Master in Survival whilst resisting the animalistic influence of an alien world, telling his enemy, "If we fight like animals, we die like animals." He displayed a talent for hypnosis on various occasions that appeared to be much stronger than in past incarnations. It is indeed fitting that this, at times the darkest Doctor of all, should not directly use physical force to implement his actions, even though he seemed to have the universe's weight on his shoulders more often than any other Doctor.

These trends continued in the Virgin New Adventures, where the Doctor would be prepared to destroy planets in the name of the greater good, and his companions were not always sure whether they could trust him. However, the mysterious Seventh Doctor eventually became slightly less dark and manipulative towards the end of his incarnation.

Habits and Quirks
The Seventh Doctor played a lot of chess, and not just on a chess board. He used it to battle his enemies and also to move his companions and his adventures around in the universe. (DW: The Curse of Fenric) He's also famous for his "rolling r's".

Mysteries and Discrepancies

 * The Doctor made a slip of the tongue when discussing the Hand of Omega with Ace in 1963, stating that 'we' had trouble with the prototype, rather than 'they' being early Time Lords. He may have been referring 'we' as a species not 'we' as a group.
 * Lady Peinforte claimed knowledge of the Doctor's actions during the 'Dark Times' of early Gallifrey, well before his assumed birth date, gathered from the Silver Nemesis statue.
 * The Doctor once stated to Davros that he was 'far more than just another Time Lord'.

Key Life Events

 * The Doctor regenerates. (DW: Time and the Rani)
 * First meeting of Ace and the Doctor on Svartos. (DW: Dragonfire)
 * The Doctor begins to show a darker side of his personality when he gives the Hand of Omega to Davros in order to ensure the destruction of the planet Skaro. (DW: Remembrance of the Daleks)
 * The Doctor discovers the Master on the Cheetah World (DW: Survival'')
 * The Doctor first meets Professor Bernice Summerfield, and Ace leaves him. (NA: Love and War)
 * Loss of his TARDIS. He takes an alternative timeline TARDIS left by his third self who, in this universe, has died. (NA: Blood Heat)
 * The Doctor defeats Mortimus. (NA: No Future)
 * Ace departs a second time, becoming 'Time's Vigilante' in order to watch over Earth for him. (NA: Set Piece)
 * The Doctor changes into a Human. (NA: Human Nature)
 * Settling old family business, the Doctor returns to the House of Lungbarrow on Gallifrey. (NA: Lungbarrow)
 * The Doctor regenerates into his eighth incarnation. (DW: Doctor Who: The TV Movie)