Peter Pettigrew
Peter peered up at the rubble that had been James and Lily's house as a rat; his black eyes blinked.
He had heard of it, all right, first thing in the morning: when the owl that delivered the Daily Prophet had flown off without demanding his pay, Peter had been intelligent enough to know that something was up. Something was: there it was, in bold letters, on the first page:
YOU-KNOW-WHO HAS DISAPPEARED
Following the title (screaming in itself) was a very informative text on Harry Potter: James and Lily's son, the vanquisher of the Dark Lord. All over the country, witches and wizards were celebrating; all over the country, toasts were being made to the Boy Who Lived. Peter's watery eyes scanned through quickly, and then he walked outside, to find a wand at his throat.
It was Bellatrix; Bellatrix, Malfoy, and Nott. Naturally, Bellatrix was hysterical; her Dark Lord, missing? Her Dark Lord, rumoured dead, killed by a mere toddler? Malfoy seemed more composed, but he couldn't hide his apprehension; Nott seemed most gleeful. They questioned him; Peter even got tortured by that bloody Bellatrix.
At the end, he confessed. He admitted that he had been the one to tell the Dark Lord where the Potters had lived.
Bellatrix had all been for killing him, really; it took both Malfoy and Nott to physically drag her away. When the three Death Eaters looked back, they saw nothing but yellowed grass; Peter had slipped away in his rat form.
Travelling the sewers, he managed to arrive at the Potters', bone tired.
And here he was, wallowing in his own guilt and self-pity.
He had betrayed his friends.
He had killed Lily and James Potter.
He had rendered baby Harry an orphan.
He had led the Dark Lord to his demise.
He had barely escaped murder from Bellatrix Lestrange's violent hand.
He looked at the remains of the Potters' house. He ducked his head; his whiskers quivered. He chewed a piece of stray wood nervously.
A full moon was rising. Immediately, he thought of Remus. How disappointed Remus and Sirius would be of him.
How angry they would be; how stupid he was.
They had been his friends.
He had betrayed them.
Now, he belonged nowhere.
Peter Pettigrew turned on his heel and crossed the street cautiously, disappearing into the night.