This is supposed to go into a longer story. But it's a different tone from the rest of it, and I don't know if it's going to fit, and I don't know when (or if) that story'll get done anyway.
So, have a snippet! Please note that I originally borrowed Harry from
ariastar, but he's gone his own way since then and she is not responsible for anything found herein.
"Master," the Doctor says urgently, and Harry wheels around sharply.
"You've forgotten the first courtesy every Gallifreyan child learns, Doctor," he snaps.
The Doctor at least has the grace to look a tiny bit embarrassed. He knows exactly what Harry's talking about.
"You address a person by the name of their choosing. I've known you since we were children, Doctor. I know your nursery name, given to you by the first person who saw your first face in this world. I know the name you used in university, the name you gave away to any passing stranger. I know the name you chose for yourself--"
The Doctor has gone pale, shaking his head. "You don't--you--that name was--"
"Did you honestly think I'd have allowed it to be forgotten?" Harry looks at the Doctor's face, and relents, just a little. "It's buried away, dark and hidden. I'd have to do a bit of work to find it. Make no mistake, though, it is there. But since the day you made your final choice, I have called you Doctor. Nothing else."
Of course the Doctor can't let it rest there. His face has gone mutinous. "You've never respected that choice. You've tried to turn me, to stop me, a thousand times--"
"Never that way. Never by using your own name against you, a name that you gave up when--"
The Doctor swallows. "Are you. Giving yours up." The words aren't quite a question.
And suddenly, he knows what he has to do. He's been thinking of Harry as a mask he's been wearing, a collection of more civilized impulses and behaviors than the madman he remembers all too clearly. Being Harry has been an option, and he's been keeping his options open.
He can't do that, he realizes now. The choice has been made somewhere deep inside him already. The Doctor may not be able to accept that, but Harry has to try to tell him anyway.
"I am. I renounce the name of the Master, for all time." He takes a deep breath, and pronounces the Gallifreyan words. Much more precise, those words are, and formal, with layers of meaning that could never be translated into any language as casual about time as English. I have never been the Master, in any possible past. I am not the Master. I will never be the Master, in any possible future.
If they had been on Gallifrey, if Gallifrey and the Time Lords had still existed, he would have said these words before the High Council. If the Council had found reason, they would have adjusted time and reality itself so that his words were truth. Ultimate forgiveness and ultimate punishment, both at once. He would have walked away from the Council a different person entirely, never remembering a previous existence.
But Gallifrey, and the High Council, had been burned away from time and space and everything except memory. There is no way to enforce his words now. No way to erase the deeds of the Master, to make it so those things had never happened. No way to make sure nothing similar will happen in the future.
His words have no weight here. They mean nothing. They only have the meaning that he gives them, as he speaks each one slowly.
There is a long silence, and he straightens slowly, gathers himself to walk away.
The Doctor speaks then, his face in shadow, his hands shoved incongruously into his pockets. The words are Gallifreyan; halting and careful, as if the Doctor has never used the language in this body. The Master has never been. The Master is not. The Master will never be.
Harry doesn't move.
The Doctor says one more word. Harry's seen it everywhere, in every formal banner and decoration on Gallifrey, but he's never heard it pronounced before. The people allowed to know that it was an actual word and not just a pretty design were few even at Gallifrey's prime; the circumstances under which it was allowed to be used were even fewer. But he knows it instantly, feels it burning into his mind. It is the Seal, the word that locks Time in on itself, so that no one, not even Rassilon himself, could change what was Sealed.
The Doctor turns slowly, stands with his back to Harry.
Harry lets his breath out slowly. They are still only words. Without the Council, without the combined power of the Time Lords and all the tools of Time at their disposal, they still mean nothing.
They mean everything.
The Master had faced the Doctor. Harry walks away.
ETA: Harry-fic in comments.