Rating: PG13 as far as explicit things go.
Fandom: Doctor Who, as AU as you need it to be.
Spoilers: Only if I'm right, and let's pray I'm not.
He doesn't remember everything, but I don't need to. I'm always and everywhere. I see, I'm seeing, I will see everything he does not, and I love him too much to set him "right." My lovely, lonely Doctor, always seeking humans because they look so much like the people he lost. Their minds are different, but they look so close. And although I have no nose — no eyes, for that matter — I know they smell almost but not quite precisely the same. He's not alone, with his companions, yet he isn't not-alone. It must drive him crazy, that, and sometimes it does.
I help him make things right, after. Memories are fixed, events shift, mistakes are unmade. Only the guilt remains, for he's a good man, and the need, for he's only a Time Lord, and against Eternity that's almost the same as being a man.
I helped him when he forced the Gray into Silence.
I help him forget every time he begs me to.
I will be there at the Fall, when he asks himself the Question and remembers it all. It will be me whom he asks to kill him before he turns into the opposite of everything he mostly, when he could, stood for. There's nobody else he trusts, and nobody else he loves.
And on that day I'll open myself to him, and for the second time in his lifeline I will speak in words. I will refuse his plea, for otherwise I would myself be alone.
He'll cry and rant and laugh, and he'll be free of his guilt and his self-imposed rules, and we'll see once more everything, and he'll remember it all as it burns.
I'm always and everywhere. I'm seeing it right now.