i. denial
Remus Lupin does not attend the Potters' funeral. Instead he spends the day at home, alone, trying to grasp how his world has gone awry. He fails time and time again. He cannot comprehend how they could all be dead when he can still see them vividly inside his head. James ruffles his hair, goofy smirk in place, Sirius following in tow, his trademark side smile threatening to evolve into a hearty laugh as Peter does his best impersonation of someone or other (Professor McGonagall? Slughorn? Lily? Lily.) All the memories seem to mesh into one and suddenly the situation becomes even more surreal. Of course this has to be a dream. Any minute now Lily will walk through that door and confide in him as she usually did when fighting against the magic world's prejudice seemed like too much. He would reassure her by voicing his own insecurities which would bring them even closer together but at least together the odds were slightly better. Or perhaps it would be James this time, with new pictures and stories about Harry, proud dad that he was. Or maybe even Sirius and Peter, who would apologise for their distant and awkward behaviour these past few months in the best way they could- one proud yet firm and unwavering, the other ashamed and submissive. Because there was no way that he could possibly loose his whole family, his whole world in one stroke. It took more than one deranged, powerful wizard to break the infamous marauders apart. Remus did not know who it was they were burying that day, but it sure as hell were not their friends. It couldn't, it just couldn't.
ii. anger
No matter how much he tried to believe otherwise, their deaths are his reality now and he is angry at them for it. These were people he trusted, he loved, he depended on. They had made him weak and vulnerable and let him to rot in a world with no constants, with no meaning. How he was supposed to face the world alone? They had taught him kindness and support and understanding in a poisonous time. He felt he would have been better off alone. At least he wouldn't be suffering as much now. Why love when it will all be taken away from you? Why trust in someone when they would betray you? No, these were not his friends; his friends would have never abandoned him like this.
iii. bargaining
He swore never to become attached to anyone else ever again. He would look for refuge in his own skin, turn his heart into a stone fortress and face the world with determination in his eyes but weariness in his soul. He would never settle for second best because, who was he kidding? He had lost it all and the golden days were over. He could live with that, he hoped.
iv. depression
His transformations hurt a tenfold more now because they reminded him of all he had lost, of all that could have been. Coming back to Hogwarts hadn't helped. There were too many memories associated with that place; every inch of every corridor reeked of a time that had been robbed from his generation, the lost children of the war. Looking at Harry was particularly difficult; the first time he had been so taken aback that he had had to pretend to be asleep so as not to confront this melting pot of emotions that were burning inside of him. The war had turned him into a coward and a fraud for it was his fault (and his alone) that he had almost lost one of his brothers to dementors and the reason why that filthy traitor still roamed freely somewhere in this unrelenting world. And he had no one to blame but himself. He could have made it right but instead he made it worse. It was with bitter remorse that he finally understood (really understood) why maybe the prejudices against werewolves were not so illogical after all.
v. acceptance
Right before he died a sudden realisation hit him: he was never going to be left behind again. His body showed the beginnings of a smile forming on his weary yet determined face. Some scars are more visible than others.