Transmasc Regulus Black Headcannons
-Regulus' deadname is Apollonia. Made a whole post about this here.
-He realized he wasn't a girl age 10, about two months before Sirius received his Hogwarts letter.
-The first person he told was Sirius, naturally.
-Sirius helped him choose the name Regulus and called him that when their parents weren't around. When he was at Hogwarts, he always referred to Reggie his brother and not Apollonia his sister, so the marauders didn't even know Regulus was afab for years. They found out one day in sixth year when Sirius mentioned something offhandedly. Not one of them ever let Reg know that they knew.
-Sirius found Regulus as soon as he got on the train for his first year and spelled his hair into a boys haircut. He'd spent his entire first year perfecting that spell for this moment.
-Sirius had told McGonagall about Reg's preferred name and pronouns before he came to school, so when she called his name to be sorted, she called Black, Regulus. None of the other pureblood cousins were close to Sirius and Reg but the Black sisters, and there are so many Black cousins of confusing lineage that no one questioned it. Regulus liked it that way, but it still hurt that not one of his distant cousins who he'd met one or two times as a kid ever asked "what happened to Apollonia?" Any that did notice assumed that "Apollonia" had been a squib and sent to muggle school.
-Bellatrix had already graduated and only Narcissa and Andromeda were at school with him. Bella would have called him out immediately and reported to his parents, but she was gone, and Andy and Narcissa never told.
-The only friend Reg told in his first year was Dorcas Meadows, Slytherin second year, because he got his period for the first time and didn't know who else to go to for help. Pandora was in her own common room.
-Sirius regrew Reg's hair on the train back home and his parents were none the wiser.
-Whenever Regulus got makeup from his parents, he would give it all to Sirius and Sirius would wear it during the school year. This continued even when they weren't speaking. Sirius would just randomly receive a super nice eyeliner by owl post.
-Pandora discovered in third year, even though Reg hadn't wanted to tell anyone else, because you never knew how they would take it. She got super suspicious of why Reg had started to refuse to take his jumper off, ever. She eventually badgered him into admitting that he felt super dysphoric about his chest, because just wrapping medical bandages around it had started to hurt and it was getting more prominent. Instead of having a problem with it, she helped make him a binder that was heaps more comfortable.
-Barty and Evan discovered fourth year when their voices started breaking and they were mocking each other's voice cracks. Regulus seemed super down and upset about the conversation, and they eventually got him to admit to being jealous of how puberty had affected their bodies. They assumed he meant that he was a late bloomer and that he was jealous of their puberties coming earlier than his. Reg's moodiness continued so long, weeks long, than eventually Barty got annoyed at him and said "Can you cheer the fuck up? It'll happen to you eventually!" and Regulus nearly started crying. Barty and Evan realized something more was going on and after asking him about it, Reg eventually said, "My problem, Bartemius, is that that will not ever happen to my body! It cant! Biologically!" Evan put years of clues together first and hesitantly guessed. When he got it right Barty was so surprised he spent a full ten seconds staring into space and then turned to Reg and went, "Don't know it this helps with the dysphoria, but it literally never would have guessed. It is not obvious." And that kinda did help a little.
-Barty found Regulus a spell that would make his voice temporarily deeper, originally intended for singers, that Regulus could use every morning. He got so used to the sound of his voice like that that when he went home for he holidays he would avoid speaking as much as possible because he didn't sound like himself without the spell. Hes parents didn't notice him getting quiet.
-Regulus worked out more than twice the amount of the rest of the quiddich team, with equipment he acquired himself, wanting to widen his shoulders and bulk his frame. Most teams don't work out off the pitch so they thought it was kinda weird at first, until it started to improved his stats insanely.
-His parents never knew. He was Apollonia to them until the day he died. His deadname was on his gravestone.
-One day, many years in the future, Luna Lovegood would search for the gravestone of her Godfather, a man who she'd heard endless storied about from her late mother. She could never find it. In fact, she couldn't find Regulus Black in any records, anywhere. Almost as though her mother had imagined him. One day, she mentioned this to headmistress McGonagall when talking about her and her husband providing magical creatures for COMC class. McGonagall found her old lists of new students and showed Luna Regulus' name, in faded black ink. She told Luna the story of how she's spent seven years insuring that Regulus could be himself at Hogwarts and his parents would never find out.
-Luna found the gravestone of Apollonia Black, and magically changed it to read: Regulus Arcturus Black, Beloved brother, friend, and godfather.