Recently mtf Sirius has been stuck in my mind (like she deserves) and I just..
Imagine the marauders in their 5th year. Sirius becomes more and more uncomfortable with who she thinks she is and feels horrible bc she always feels what she thinks is hatred (but is actually jealousy) every time she looks at the girls in their pretty dresses and skirts and makeup.
James gets closer to Sirius 'sister' and they become friends (and maybe more but Sirius doesn't need to know). James helps Regulus to accept who he is (he knew already just couldn't accept it). And when he cuts his hair, starts wearing the boys uniform and changes dorms, telling everyone that his name is now Regulus Arcturus Black. He doesn't think about their parents once and Sirius is so fucking proud but it tucks at something inside her.
She takes the makeup that Regulus wanted to throw out and a set of Regulus wrong uniform and when she looks in the mirror it looks a bit weird and wonky but it clicks and she knows now what that sense of longing was and she feels like she is another step closer to freeing herself from her parent's.
Telling her friends is way more nerve-wracking than expected but she manages. Everyone accepts her and Remus doesn't break up with her either(which was one of her worst fears).
And you bet your neerdy asses that Sirius and Regulus bond a hell lot over them both being trans.
