The Doctor, in Doctor Who, brings hope and safety to all time and space. Each version of The Doctor retains the tragic and curious nature of being a savior, despite their fresh faces and unique personalities. The incarnation of The Twelfth Doctor, played by Peter Capaldi, was sarcastic, witty, and candid, as well as haunted, determined, and forgiving.
He had his fair share of painful choices to make, wonderful lives to save, and companions to go on adventures with. He was The Doctor whose face served as a constant reminder of hope, but like all Doctors before him, his faith was tested.
He Watched Clara Die
The Twelfth Doctor and Clara were extremely close, and they would do anything for each other, both being strong-willed and stubborn in their decisions. So when The Twelfth Doctor found himself helpless to save Clara from the Quantum Shade, he was devastated.
Clara had made a choice that he could not undo and it was a sacrifice he should have foreseen. With a teary farewell and a final plea to The Doctor not to seek revenge, Clara faced the Raven.
He Never Knew Of Missy's Final Allegiance
The Twelfth Doctor and Missy had a complex relationship. But ultimately, their interactions made Missy regard the universe with more decency. "Why not, just at the end, just be kind?" The impact of The Twelfth had on her was just enough to influence her.
When Missy was faced with the question of allegiance, she chose The Doctor over her previous incarnation - The Master. The tragedy was that The Twelfth Doctor never saw her make this choice, as The Master killed her.
He Forgot Clara
Clara and The Doctor's relationship was verging on the edge of a dangerous commitment. The Doctor even shot a fellow Time Lord to save her. Events transpired and The Doctor wanted Clara to forget him and live a normal life, hidden from the wrath of the Time Lords. Clara refused, insisting on remembering her past.
Together, they decided it would be fair if chance chose who would forget the other. With both pressing the neural block device button, it was The Doctor who forgot his beloved companion.
Coming To Terms With Bill's Fate
Bill was a curious, inquisitive, and intelligent companion to The Twelfth Doctor, and her fate was a shocking development. On an adventure with The Doctor, Bill was shot in the heart and converted into a Cyberman. But her strong will and resilience allowed her to keep her consciousness.
The Doctor and Bill reunited and fought the Cybermen together. Bill cried over The Doctor's "death," and was saved by Heather. But The Doctor remained wary of her fate, unable to accept the glass memory avatars of Bill and Nardole. He thanked them but knew he had to leave them and go onwards alone.
Dying Repeatedly In The Confession Dial
The Twelfth Doctor was determined to save Clara and he persevered in this endeavor. It didn't matter that he was trapped in a Time Lord confession dial, he would find her. The Doctor awoke every new cycle believing himself freshly transported inside.
He would outrun the creature of his nightmares, swim among the skulls, find his dry clothes, punch the diamond wall, and burn himself for the energy to create another copy of himself. He was killed and cloned on repeat, and every time he realized the truth of what he had to do, every time he did it. "How many seconds in eternity?"
Facing River Song's End
While The Tenth Doctor was the first to meet River Song, The Twelfth Doctor was the last. He was The Doctor with all the memories of their adventures together from his previous regenerations.
When The Twelfth Doctor interacted with River Song, she didn't know who he was, as she had never seen his new face. When she finally remembered who he was, it came time to say goodbye. "The towers sang, and you cried. You wouldn’t tell me why, but I suppose you knew it was time. My time. Time to come to the Library."
His Regeneration
"Can't I ever have peace? Can't I rest?" The Twelfth Doctor was shot during his battle with the Mondasian Cybermen, but he refused to regenerate. His interaction with The First Doctor and their time together helped both of them accept their fate and regenerate.
The Twelfth Doctor's regeneration speech was the embodiment of everything he tried to be and wanted for his next incarnation. He always excelled at touching speeches, and he gave one to his future self in his last moments. "Never be cruel, never be cowardly."
He Was Betrayed By Clara
After Danny died, Clara's grief consumed her. She decided to blackmail The Doctor into saving Danny, using the TARDIS keys as leverage. She threatened to burn all seven keys in volcanic lava, and she did. Only it was all a dream state.
"You betrayed my trust, you betrayed our friendship, you betrayed everything that I've ever stood for." After they awoke, The Doctor decided to help her save Danny his way. "Do you think I care for you so little, that betraying me would make a difference?"
His Good Faith Was Manipulated By Davros
Despite his steely appearance, The Twelfth Doctor was exceptionally compassionate. This compassion extended to even his oldest rivals, including Davros.
When The Twelfth Doctor learned of Davros's final wish to see the sunrise before his death, he provided enough regeneration energy to make it possible. But his good faith was taken advantage of and The Doctor needed to be saved by Missy.
Haunted By His Past
The Twelfth Doctor needed to know if he was a good man. He needed to know the truth. He was a version of The Doctor who was self-reflective and knew himself to be capable of great manipulation. He was haunted by his past in the form of his regeneration form and constantly reminded of the standard of who he should be.
Every time he looked in the mirror, the face of Caecilius stared back, and he tried his best to honor that. Any deviation, any failure, he felt was twofold in its pain.