I got my favorite soulmate one! well its not my favorite actually but I can change it, so its 'Anything your soulmate draws/writes on their skin it appears on the other's skin' so Im thinking Moonwater for this one, where Regulus was very confused why marker keeps appearing on his arms. He gets punished for it and little Remus is confused why his arms are all red.
Then Remus gets bite by a werewolf, the scar transfers to Regulus but he isn't effected he only has the scar. Luckily the mark is easy to hide so he tells only Sirius and then every month he runs to Sirius's room crying and confused as new marks appear. And after the full moon Remus feels guilty for every scar he might have given his soulmate.
Hogwarts comes and Sirius meets Remus who he doesn't know its a werewolf yet and goes on and on about how cool his scars too and how his little brother has scars too. Blah blah Regulus comes but they don't meet immediately, nore do they put the pieces together (or Remus does but doesn't want to admit he is a werewolf).
Years later and its after the Prank, Remus hasn't been close to Regulus honestly at this point he expected it to be better since he doesn't deserve a soulmate and Regulus probably would never want him. Then he has a run in with maybe Pandora and she brings him around her friend, and he gets closer to Regulus and come to find out Regulus knows he is a werewolf and was scared to confess because he thought Remus didn't want him.
