Peter Pettigrew
Peter Pettigrew hates Remus Lupin.
It's taken him almost nine years to realize, but now that he has, he knows it is completely and utterly true. He hates Remus with all his being.
It's honestly not because he's a werewolf. He swore in his first year that it made no difference, and those words still hold true. He truly doesn't understand why the wizarding world hates them so much, isn't the monthly bone-crushing transformation enough punishment?
No, it's definitely not because he's a werewolf.
In all honesty Peter should probably feel closest to Remus. After all, they are both social outcasts. The only reason either of them were popular in school is because of James and Sirius. It would be more logical if Peter hated them for their popularity, but no, Peter's hate is directed at someone like him.
Maybe that's the root of Peter's problem.
James Potter and Sirius Black had no reason to open their arms for Remus or Peter, but they did. Maybe Peter's hatred stems from jealousy, maybe he felt like the two boys should have only accepted one outcast, devoting all their attention to him. It made sense. Peter has always felt something stabbing into his stomach whenever James or Sirius direct their attention at Remus instead of him. The stabbing sensation has only gotten worse as years go by.
Sirius seems to like Remus better than Peter. Maybe that's because Peter fanboys over James, or maybe Peter fanboys over James because Sirius like Remus better. Even Lily liked Remus better. In fact, Peter is sure that if James and Sirius hasn't accepted Remus that Lily would have, so why not cast him out and let Lily have him. So maybe Peter's hatred does stem from jealousy.
Or maybe Peter is jealous because of his hatred towards Remus.
Either way it's his hatred of Remus that makes him whisper poison in Sirius's ear.
"Where is Remus right now?" "I haven't seen Remus in a while, I wonder what he's up to." "He seems more distant than he used to."
He can see it the longer he asks Sirius these innocent questions. The undying trust that Sirius use to place in Remus was fading.
Bingo.
Maybe the hatred doesn't come from their similarities, but their differences. Remus is, after all, a lot smarter than Peter. He will admit that. Remus's help is the only reason he's gotten this far at Hogwarts, the only thing he's good at is charms, so maybe he should be grateful that Remus was there to help him, but he isn't.
Stupid Remus has always been better at school than dumb old Peter. Remus had all the teachers in the palm of his hand, he was smart, and polite, and they all felt so damnably sorry for him in his condition, it was almost sickening. It's probably actually why James and Sirius kept him around. He was just so different than Peter.
But that's just jealousy isn't it, jealous that Remus is so much smarter.
But it's not his hatred that brings him to the Death Eaters, it's fear. He, Peter Pettigrew, is afraid of what the Death Eaters can do to him.
It wasn't hatred that made him spill the Order's secrets, it was only hatred that made him plant seeds of doubt towards Remus, and stupid Sirius ate up every word of it.
As if Remus would ever betray James and Sirius. After everything they'd done for him, why would Sirius ever believe Remus would turn.
No, Remus was brave, he would never allow the Death Eaters to bully him into betraying the first people to ever trust him. He was too brave to roll over, to bend over, to hang himself from the gallows like Peter had.
'Maybe that's why I hate Remus.' Peter thinks as he approaches the rendezvous point. 'Because he's got the bravery of a Gryffindor, while I'm about to sell my friends out to ensure my own safety.' A dark figure in a mask approaches, and Peter knows there's no going back.