A/N: Collective headcanon. We all know It's true.
Double Life
The battle was years ago. When he began his new life, just after faking his own death mind you, he had fully intended to leave his past behind him. Unfortunately, things have never worked out for him the way that he would have liked.
Now he is paid to pretend to be the man he once was, watching imitations of people that he used to know. The castle that they have is nothing as splendid as Hogwarts, but of course that would be expected. The young imitation-Potter looks very much like the real one did at that age—except for his eyes. This boy does not, by any stretch of the imagination, have Lily's eyes. As far as the other actors, Granger isn't nearly beaverish enough, while Weasley is too stocky. The faux-Minerva does well enough. And it would be expected that no one could truly play the part of Dumbledore.
It's unnerving, having to memorize more dramatic versions of things that you've already said, written by someone else's hand. It's even stranger to have the Muggle camera pointed at you, and not be able to use magic, even when magic is required.
And yet, as the years go on, he finds himself becoming very attached to all of these people. He enjoys watching the children grow up, just as much as he enjoyed looking after the real Golden Trio. Eventually, he lets his guard down and allows himself to make friends. Laugh. Even try out the internet…although when he discovers fan fiction, he promptly gets rid of his computer.
Ironically, pretending to die again is the one thing that helps him reconcile with his past. He will be quite sad when this is all over…This has been his life for over a decade. A shallow, yet wonderful imitation of the life that he lived for forty years.
It's his last day on set. He takes a good deal of time wandering, fixing every detail in his memory. This will be just as hard as leaving his last life. At least this time he will have his Lupin doppelganger to go out with him.
He stands in front of the cast and crew, as the director makes his goodbye speech. It's quite touching to hear such a cheer go up when he is dubbed Hogwarts' favorite potions master. Before he can leave, he feels like he's hugged everyone at least twice. Finally he breaks away, to stand with the tall figure in the back of pretend-Dumbledore. They've become rather good friends.
"What's next?" asks the older man.
"I'm not really sure…" the younger replies, a distant gaze on his face. "I'm still trying to figure out what I want to do with this life. I still have some…things to take care of."
A true shadow of Albus Dumbledore looks at him, a knowing glint in his eyes.
"Even after all this time?"
"Always."