"I'm losing myself", thought the man who once was the Doctor. Or was the Doctor him?
Having spent the decades of his existence rejected and stranded in another universe, because he was considered "too dangerous", the multiverse's only human-Gallifreyan metacrisis entered his baby TT capsule, grown off a bit of coral from the TARDIS. Ah, the TARDIS. Sometimes when he was falling asleep he could feel her presence inside his head. But it was never his own head, it was HIS!
It was all the Doctor's fault, tossing him like a bit of trash into Pete's World. Locking him away out of fear of what he could become. Out of fear that he would fulfill what the Master had said all those centuries ago.
He was losing himself, and he knew it. Human, Time Lord, something in the middle, all his memories, and the different ways of thinking, as well as a strong feeling of abandonment, were taking their toll on him. Soon, this could be a problem.
"John?" came a voice outside the capsule, along with a soft knocking.
Ah, Rose. Rose, his dear friend over these last decades, stranded in a universe not her own.
Stranded with him.
At first they thought they loved each other, but he knew she was still a child, and even the human part of him, courtesy of Donna, thought of Rose as a younger sister. Rose entered her twenties, found Carl, and the two of them got married, had a nice, loving, human family. But they still stayed friends, lifelong friends, even now that she was in her fifties, and he was a human biologically sixty-one years of age. He lived in a wing of the mansion she inherited when Pete and Jackie passed away.
"John Alastair Smith, haven't you eaten recently?" asked Rose, ever looking out for him. She noticed his worsening mental stability some time ago, and seemed to be mothering him a little.
"No!" he shouted abruptly, before remembering who he was talking to. Softening his tone, he tried again.
"No, Rose. I haven't. It's frustrating, having to eat so often."
"I know," she replied. "I remember how long it took you to finally start sleeping every night: five months and twelve trips to the hospital. I had hoped eating would have become a habit by now."
"I'm sorry, Rose," he said. "I'm just in one of those moods today."
"Oh. Sorry. I'll leave you to your TARDIS tinkering then. There's a sandwich in the kitchen if you get hungry." She replied, leaving. "I'll see you later, huh?"
"Yeah."
TARDIS.
Oh how he wished she would stop calling the capsule by that name. It wasn't her, she was gone forever, with him. She could never be replaced, and he could never insult her memory by giving this… this copy the name his dear Susan gave for her.
Susan…
He missed her so very, very much. He missed them all, ever last one of them. But they were never his, they were the Doctor's friends. And he was not the Doctor.
John Smith fell to the floor, weeping in sorrow of all he had lost.
He was losing himself, and he knew it well. His mind had long since lost the guiding voices of his past selves. Except he only really had the one self, no matter what his memory told him. Who was he, anyway? Some rejected soul-graft, or a butchered binary clone tossed away? No, he could make himself a new man. A better man than the Doctor ever was. The Doctor was a fool! He didn't deserve any of it: the immortality, the freedom, all he did was wander about, get his friends killed, and throw away the rest of them!
He didn't deserve this. Rose didn't deserve this. But she was happy, she now belonged in a way he never could. She had a family, a life that she deserved. But he? John was no human, and he was no Gallifreyan. For all his physical humanity, he could never live like them. Such fleeting lives. No, he couldn't stand it, he wouldn't have the first inkling of how to do it!
He would leave tonight.
And why shouldn't he?
Simple, really, to adapt the universe-hopping technique taken from this universe's Torchwood and make it safe for inter-dimensional travel, without opening rifts in time. It was easier than 11-dimensional quantum trigonometry, something Time Tots master before they even enter the Academy.
And then?
Then, it would be simple to find the Doctor. After all, who was there to stop him? The Time Lords couldn't, they were gone! Nor could they help him in his quest for his rightly-stolen lives. That's what they were, stolen!
"…taken from somewhere…"
They should have been his, not the Doctor's! Instead, he decided to waste a regeneration. Why? So he could keep the same face? Why was that even important? After all, Gallifreyans didn't recognize each other from physical appearances, but by telepathy! What a vain little prick the Doctor was in his tenth- technically, eleventh- life. Wasting a regeneration for the sake of vanity, and allowing a metacrisis to happen? No, if the Doctor could be so cruel and selfish as to just leave a bit of flesh infused with regeneration energy lying around, knowing very well that it was just asking for this to happen, and then rejecting the new being that resulted from it all, then the Doctor did not deserve his lives. Any of them.
"…Of the darker side of…"
It would almost be a kindness, wouldn't it? Taking away the Doctor's lives, a kindness to the universe. All the killing, the cruelty, it didn't begin until the cruel little manipulator. That's where it began, and that's where he had to stop it. From there the Doctor became that forgetful little death magnet, then the one who killed his own people! Not to mention the emo grump and that know-it-all chatterbox wanna-be-human he was stuck looking like. Compared to them, even the proud brash man in the multicolored coat, stuck with mental trauma left over from the violence of his previous life, was a saint.
"…his twelfth and final…"
Yes, that's what he had to do- rid the universe of the Doctor. But why waste all the Doctor's lives, and the lives he saved before? Why, he could take them for himself, and kill two vortisaurs with one anomaly! Extend his own lives-span, and prevent the Doctor from ever committing the atrocities that he knew would happen. They were technically John's lives too, so why didn't he deserve them?
"An amalgamation of the darker side of the Doctor's nature…"
The words the Master once spoke in a courtroom long ago, in John's- no, the Doctor's memories came back to him, and he suddenly knew, for the first time in his existence, who he was, and the answer no longer frightened him.
He was the Valeyard.