He was going to make this mistake. He could see it, and he did it anyway. He turned fully back into the room.
"And even though Harry hit him," Sirius seethed. "He's still spouting off the same bullshit that you've been saying all along. That this isn't the Peter who betrayed James and Lily." He clenched his hands hard at his sides.
"Do you think he just woke up one morning and decided to do it, Remus?" Sirius pressed. "Do you think he suddenly just learned how to be a good liar who knew how to manipulate? He planned it, Remus. He fucking planned it. He used the traits that he always has fucking had. It's not this brand-new Peter that betrayed us. It's the same fucking Peter that rode on the train with us when we were 11-year-olds."