Remus didn't know how it always came to be that he was the last Marauder. He'd been the last 'true' Marauder for the first time on November 1st, 1981.
"I'm sorry, Remus," Dumbledore says, rising. His glittering blue eyes relay all the condolences not spoken aloud: the fact that Remus is the last Marauder, the fact that he can't take in Harry because the Ministry won't allow it, the fact that Peter-little timid Peter-stood up against a raving murderer and got blown to bits, the fact that said murderer was actually Remus's best friend, the fact that said best friend got sent to Azkaban without a trial.
Remus nods, and Dumbledore lets himself out the way he came in: through a whirlwind of ethereal green flames.
And now Remus is free to truly break down. He puts his head in his hands and shakes with repressed sobs.
Alone.
Remus's whole world has been uprooted. Sirius is innocent. Peter was the traitor.
Sirius is innocent.
Peter is alive.
He isn't alone after all. He doesn't like to think about Peter, but he has Sirius, and never mind that the man is on the run from the law with a hefty price over his head.
The last Marauder? Remus scoffs at his past self. Oh, ye of little faith.
In the days following Sirius's death, surrounded by the mourning and filled with weariness, Remus can't help but let out a bitter laugh at the irony of it all. He is the last true Marauder again, although this time the traitor is the watery-eyed rat and not the great shaggy dog. But it makes no difference.
He is the last Marauder again.
He doesn't tell anybody, hardly mentions it to himself, but a small worm of hope festers in his ragged chest. He hopes for another misunderstanding, he hopes that maybe an outsider was the spy, he hopes that Peter will return and stave off his loneliness.
But he knows it cannot be. Peter was the spy. Peter was the traitor.
Remus is still alone.
Peter is dead. The news isn't highly publicised, but it reaches Remus's perked ears nevertheless. The worm of hope in his chest wilts and rots, and from its decaying remains a sense of relief blossoms. He hates to think it, but he is satisfied that the blame of the Potters' murders rests firmly on one pair of shoulders and will not be upset any time soon. Guilt tinges the edges of his emotion, and with the guilt comes the repetitive mantra: He is the last Marauder once more.
And this time it is absolute. There will be no more returns from the dead, no more cleverly-hidden secrets to reveal.
No more Marauders to console Remus.