Regulus runs from home before Sirius does. He moves to the muggle world and meets Noah. Noah adopts him but he keeps his name but everyone knows him as Stiles Stilinski. He still goes Hogwarts but he looks different so no-one recognises him until Sirius does. After Sirius recognises him the pack come to Hogwarts. They are shocked. Two days later James asks him out and he accepts.