In his century or so of being alive, Sirius has never had friends quite like these. Sure, he’s had friends before, it was hard not to make some connections over the decades, but these ones, were easily the best.
They all know he’s a vampire. He originally planned on not letting that one out but after coincidentally making friends with a werewolf the two decides to be honest with each other and their other friends, who took it surprisingly well for a bunch of 12 year olds.
But a couple years later and a lot of things had changed. Sirius became even more of a rebel in his parent’s eyes, not feeding on human blood, making friends with humans. Eventually he got sick of their actions and left for good.
Living with James was an adjustment but one he would be forever thankful for. However the more his friends got older the more obvious it became that he would not.