My attempt to see why Pettigrew went from being a Marauder to being a Death Eater. Review if you have time :)
The world of Harry potter belongs to Rowling, not me.
Looking back, he knew where it really began. It had been those nicknames.
They'd sat around, grinning and proud and slightly shocked that they'd actually managed it. Three illegal animagi, and one werewolf. And James – or maybe Sirius – had decided that they needed nicknames, because, well, because there was no way that they could be able to do something this cool and not shout about it.
But shouting about it would end up with a lot of trouble, so someone suggested nicknames. Something secret, something no one would understand - because who would guess this? - something that they could use and laugh about and something that would mean them. They picked names out of a hat, gave themselves a week to come up with the names.
Peter spent so long thinking. He tried and tried and tried. He wanted to think of something good, something slightly cool and mysterious, but not too obvious. Something explicable, that could be easily shrugged off.
And they'd sat around once again, and he'd written down 'Moony' and sat back, feeling proud. Remus had thought about it, and asked why, just as he had when James had come up with 'Padfoot', and as he hadn't waited to be asked when he'd come up with 'Prongs'. And then it was Sirius' turn, and he scribbled down 'Wormtail', and Peter knew, he just knew, that Sirius had forgotten, or not bothered. Remus didn't even ask.
It would have been better, Peter had often thought, if he had asked. Because Sirius would have made something up – anything – made it sound like he'd really thought about it. And maybe Peter could have pretended to believe him, pretended so well that he forgot he was pretending.
Wormtail. What kind of nickname was that? It sounded stupid. It sounded dull. It was laughable. It was hard to pass off – not like a love of astronomy, not like being scarily good at sneaking around, not even like a reference to having been caught in barbed wire once when flying.
And that was where it started.
Things were added, over the years. Little things, mostly. Times he was ignored, times when he just couldn't keep up. Times when he was alone, and suddenly realised he was nothing. All those little things that added up to Wormtail.
The sneak, the rat. Small and scared, always hiding and looking for protection.
And the dark times came, and he found protection. It cost the previous protectors, but he told himself there was nothing else to do. He wasn't strong. He wasn't brave. He wasn't clever, or cool, or even funny.
He was just the little boy running along, half a step behind, always looking for approval and never finding it. The tag along, the scapegoat, the one who had to have everything explained a hundred times. The one who was left alone, and when alone, was crushed by it, so took the only escape route he could find.
He was Wormtail.