He was originally the most timid of the predators, but because of his friends' persuasion, he joined the most dangerous organization in the wizarding world. But in danger after danger, his friendship was in jeopardy, and the low self-esteem he had in school finally tore away the last tender affection at the height of the war. But in the end, he lost not only his friends, but also himself.
Although I don't like Peter Pettigrew, I really like the Marauder, but unfortunately Sirius's perspective is incompetent, so I can only try it from Peter's perspective.