So Voldemort acquired a few children

Trolls are bad and pranks go wrong

Nat was pleased with how Hogwarts was going, she already had a small group of children who were afraid of her and were to help her with her plans of world domination for the low, low price of almost guaranteed survival. She'd seen Snape taking pictures of her chatting with the Bloody Baron happily, the Bloody Baron was her only actual friend. She wrote to her father every night, just like he'd asked of the three of them. She wrote about how she liked herbology and was the top of the Potions class in her year. 

The Bloody Baron was fond of Nat according to the other ghosts, who kept trying to talk to her because she was someone who the Bloody Baron actually enjoyed conversing with. 

Harry had already gotten up to some shenanigans, fighting a troll, Voldy had been angry when he'd heard and told Harry that should it happen again, Harry was to simply use Avada Kedavra, just like he'd taught them. 

Harry wrote about his grades and happily wrote that he was at the top of their defense class in the Gryffindor's first year. He wrote about how happy he was to have passed his latest herbology test, as it was his worst subject he was also quite good with charms. 

Hannah wrote about the pranks she'd pulled with the twins and Lee. She wrote about how she was at the top of the charms class in Gryffindor's first year, and quite good with astronomy as well. Hannah wrote about how Nat decided to befriend a ghost and how she'd befriended Nearly Headless Nick, they'd both been at the man's deathday party, Nat being Bloody Baron's plus one and the ghosts had wanted to meet her. Hannah thought the deathday party was fun, getting to know the ghosts had been fun and it had been funny to watch the Bloody Baron dance with Nat, which should be impossible because Nat's alive, but whatever it might've been something about Nat being one of their dad's soul thingies. 

Hannah made sure to write to dad about that, and about how Nat could interact with the ghosts physically, hence the dancing. Hannah didn't know how on Earth Nat knew how to waltz and foxtrot but she theorized it might've been Lucius's fault during the times the blonde had watched them. Hannah normally painted in her room and Harry after he grew out of the trying to murder Lucius faze sat in her room with her, still not liking Lucius much. 

Hannah wrote about how she'd seen Nat being held by the Bloody Baron, who was floating at the ceiling to get Nat away from creepy older years who had been trying to hit on her because she's always looked older than she is. She gave names, knowing the consequences that would most likely happen to them via their dad's yandere rage. 

Hannah wrote about how people were fawning over Harry like he was some sort of bloody zoo animal that knew how to do tricks. Hannah thought it was annoying, as did Nat, who hung out with them sometimes when she wasn't hanging out with the Bloody Baron. Hannah had the feeling that the Bloody Baron would eventually get lectured by Voldemort into protecting Nat...he was weirdly more protective of her than she or Harry. Hannah decided it might be another thing that might have to do with the soul thingy. 

Hannah looked up from her parchment and rolled it up before hooking it to Prometheus as the twins walked over she opened the window for Prometheus. "Prank time?" she asked with a grin. She knew her sister was going to hate her in the morning but it would be worth it to see her with fucking antlers along with the rest of Slytherin.  

*The Next Morning*

Nat woke up and walked into the Great Hall, the Bloody Baron floating next to her she sat down, being the first Slytherin awake and the Baron said "Nat, I believe something has happened". Nat hummed "What do you mean?" The Baron simply said, "It would appear you have antlers". Nat blinked before narrowing her eyes and looking over to the Gryffindor table, where only a few Gryffindors were starting to file in. 

When she saw Hannah she glared and stood up, having finished breakfast and walking over before grabbing Hannah's shirt "Why. Do. I. Have. Antlers. Hannah?" She said in a calm tone that for some reason scared people more than it would should someone be yelling. But Nat never got explosive angry unless someone had pissed her off past her limits, and that had only happened once. 

Harry winced when he saw the antlers and Hannah said "Chill, they should go away in three hours". Soon all the Slytherins had antlers including Snape, who looked ticked. The Bloody Baron picked Nat up and said "Nat, you shouldn't fight in the Great Hall, it's unbecoming". Nat's feet dangle a foot off the ground as the Baron floats at his usual level before allowing herself to be carried off to where her first class of the day would be, not noticing the stares she was getting from all of the professors as well as most of the student population. 

Snape immediately pulled out parchment and wrote 

"Dear Marvolo, 
Your shortest child can physically interact with ghosts, the Bloody Baron just picked her up and carried her away to stop her from fighting Hannah, who gave all of us Slytherins antlers for the next three hours. What the actual fuck is going on?
Sincerely, Severus Snape"

He handed it to his owl immediately before leaving the Great Hall. 

By lunch, all of the Slytherins besides Snape and Nat didn't have antlers. When Nat saw this she glared at Hannah until the Baron decided that Nat needed to be removed from the room, seeing as she'd finished eating and he didn't want a fight between siblings...those got scary...especially with girls. 

At dinner, Nat was the only one who still had antlers. She was pissed and the Bloody Baron spent most of dinner floating by the candles holding her bridal style so she couldn't go after her sister for the stupid prank. Snape looked like he was terrified of what this meant. Dumbledore just stared at the duo. The Baron looked like he was sitting in the air while holding Nat. No other person had ever been able to touch the ghosts or be held by them. Nat spent most of dinner with her hands crossed and pouting at the Baron, who merely rolled his eyes and said "I don't want to see what you could do to her with those antlers, deer antlers are meant for two things, protection, and looks. They're sharp." 

When Voldemort got the letter he spit out his tea, his child dancing with ghosts was one thing, but being actually held by one was insane...also he was worried about Hannah, the girl should know better than to prank her sister in a way that said sister could use the prank as a weapon. 

Snape took a picture of the Baron holding Nat while she pouted and still had antlers. 

A week later Nat still had the antlers and the Baron had to resort to grabbing Nat around the waist and holding her in his lap almost the entirety of every meal so she wouldn't attack her sister or the twins. The three who had started the prank were worried they were going to be murdered. The Baron supervised Nat in the halls and Snape stuck to sticking Nat to her spot and just bringing her the ingredients for the potion when they did potions to prevent Nat from using her only chance to attack her sister for the antlers. 

It took a month for the antlers to finally disappear by themselves. Nat's homicidal rage left a week after that. The Baron was proud Nat hadn't murdered her sister for the antler deal and Nat was declared off-limits for future pranks after this because antlers that were supposed to last for three hours lasted a month. It was December first now and everyone was glad that the antler mishap was finally over.