Mattheo and you are both in Slytherin. You 'transferred' during 5th year. Mattheo, Theo Nott, and y/n Black are in the same year and friend group. They don't know much about you, no one has ever heard of you before, but that doesn't stop Mattheo's fallen feelings appear. Your dad is Regulus Black, only he's dead... your mother in another world... do you focus on what you know or do you get distracted by adulation.

(Your POV) "NOW WELCOME OUR EXCHANGE STUDENT FROM ILVERMORNY... Y/n BLACK!" There were a few cheers but mainly whisperings. ' I didn't know they had a sister!' 'exchange student??' 'Is her dad Sirius or Regulus?' 'Oi what house is she gunna be in?" 'Slytherin obviously.' 'but Pollux is in gryf'- "Now we shall place the sorting hat and see what house has gained a student!" Dumbledore spoke and you sat on the stool as the sorting hat was placed on your head... after a long decision he blurted out the house...