"That's quite the voracious appetite you have," Oleandra remarked, eyeing Astoria's sharp fangs. "Have a drink of water before you choke on a bone, or something."
Viviane's last act before leaving had been to forcefully wake up Astoria so that she could eat an éclair to replenish her energy. As soon as she was able to somewhat get to her feet, Oleandra and Daphne had dragged her to the Kitchens, where Astoria had devoured ham after ham. With enough animal matter in her belly to complete her transformation, they had then taken her to the Hospital Wing to make sure she wasn't dying.
"Honestly," muttered Daphne angrily. "Can't Madam Pomfrey see this is an urgent case? Why is she bothering with that boy's ingrown toenails, instead of coming to see us?"
Oleandra could see why Madam Pomfrey was making them wait while she was taking care of another patient. Astoria was now hale and hearty; perhaps even more so than before she had taken the potion. With every bite of ham she took, her complexion regained colour.
The Bloodline Atavism Potion, or rather the Ovid's Tincture, its main ingredient, truly was a miraculous invention. What was currently happening to Astoria was more than simple regeneration; it was a complete rebirth of the body. This was probably due to the Phoenix ashes component of the potion, when Oleandra thought about it. Astoria's necrotic tissues, which should have been impossible to heal back to normal, had turned into healthy tissues. All that to say, apart from feeling slightly peckish, she was fine.
"Well, out with it," said Madam Pomfrey as she took a closer look at Astoria. "What's happened to you? Stray curse? Or one of those Weasley twins' diabolical confections, I suppose? They haven't been bullying you, dear?"
"That's not it," Astoria said, shaking her head. "Er…"
She looked at Oleandra and Daphne in turn, as if to ask permission to say what had actually happened to her.
"She drank the same potion as I did two years ago," Daphne said decisively. "We just wanted to make sure she was okay."
Madam Pomfrey alternated between looking at Daphne and Astoria. Green head, red head. Green head, red head. In what world did potions provoke such different results? Still, it was her responsibility to ensure that Hogwarts students remained healthy. But as her examination progressed, Madam Pomfrey's stern expression turned into a frown, before finally turning into disbelief.
"That's not possible!" she sputtered. "If blood maledictions were so easy to cure, then nobody would have them! I didn't ask too many questions about what you'd done to yourself two years ago, but this time I must insist. What have you done to yourselves?"
As serious genetic defects, blood maledictions were generally thought to be incurable. Certain people thought they were caused by actual curses being transmitted through one's genes to one's descendants, but nothing could be further from the truth.
The noble families of today were generally descended from the Muggles who had been turned into human weapons bearing Fantastic Beast blood during ancient hybridization experiments led by Roman Wizards in Antiquity. Blood maledictions occurred when two or more Fantastic Beast bloodlines vied for dominance in a human's body. They would fight and feud with each other, which would almost always end in an early and painful death for the host body.
However, in rare cases, one bloodline would actually win; but without the others to keep it in check, it would grow in strength unstoppably, much like a cancer, and eradicate the host's humanity. The afflicted would eventually slowly and irrevocably transform into beasts, with no way to change back. These people were known as Maledictuses; a fate generally considered to be worse than death.
Incidentally, Maledictuses have nothing to do with Animagi; the magic to Transfigure oneself into an animal at will is a branch of magic that has existed for as long as humans have been fascinated by animals.
"I'm afraid that's a family secret," said Daphne happily, now that it was confirmed that Astoria would be okay. "Isn't that right, Sis?"
"Er…" said Oleandra. Nope, it definitely wasn't.
"But think of the people your treatment could save," Madam Pomfrey insisted. "Why hoard such important knowledge? You could all get an Order of Merlin, Third Class, at the very least! Second class, even!"
The problem with using the Bloodline Atavism Potion was that it transformed one into a human weapon. Granted, Daphne wasn't yet at full power, but one day, after she'd accumulated untold amounts of strength with her now apparently infinite lifespan, she would become stronger than any one person had any right to be. Voldemort had certainly been on his way to invincibility, before Harry had stopped him.
As for Astoria… Well, Oleandra wasn't quite sure what she was currently capable of, but as far as she knew, Kamaitachi didn't have extremely long lifespans like Wood Nymphs or Basilisks, so at least she wouldn't become a living god like her older sister.
"This must never become public knowledge," said Oleandra firmly, giving Daphne a sidelong look. "It's too dangerous to let just anybody have that much power."
Daphne looked quizzically back at her; she didn't feel that overpowered. The Hogwarts teachers still felt like unsurmountable walls to her; as in, she didn't see herself winning a fight against any of them; except perhaps Professor Trelawney… or Professor Hagrid, if she managed to tie him up in vines and drag him underground before he could react and break out of his restraints.
"Fine, do as you will," snapped Madam Pomfrey. "Now unless you're sick or injured, you've got no business sticking around here; so out! You've wasted enough of my time already!"
The three sisters were promptly ejected from the premises. Madam Pomfrey was like an angel to her patients, but to anybody else, she could just as easily turn into a devil!
"Well, that was rude of her," said Daphne in huff.
"Astoria, your eyes," Oleandra gasped. "I hadn't noticed before, but they've…"
Since Astoria's eyes had been rolled up in the back of her head the last time Oleandra had got a good look at them from up close, she hadn't noticed that Astoria's pupils had turned into horizontal slits.
"Oh no, it's getting late!" Astoria exclaimed upon looking at her watch. "I've got to make it back before the Fat Lady falls asleep or I'll be stuck sleeping outside in the hall like Neville when he forgets the password okay bye now!"
Oleandra and Daphne barely had time to blink before Astoria had sprinted down the hall and disappeared around a corner. Wow, she was really fast now!