"... Is it asleep?"
"Yes, I think you didn't see it wrong, Mr. Richard."
Dobby answered with a slightly trembling voice, nervously rubbing his collar, the purple clothes with a white necktie becoming somewhat wrinkled in his hands — ever since starting to earn a salary from William, Dobby never lacked Galleons again, thanks to his good habit of saving money regularly, as well as William's generosity.
In fact, William's generosity is normal, considering that Dobby is now the only employee in his "suitcase zoo."
From feeding the Moon Enchanted Beast that needs four meals a day to scooping the litter in the Nundu's sandbox mountain, Dobby took on almost all the tasks of caring for the creatures, since William is not the kind of Pure-Blood fool who can't even take care of himself, and most of the time he settles his meals in the great hall — which led to Dobby being too idle after he first started following William.
A House-Elf with nothing to do — although Dobby always pursued freedom, this was something he had never anticipated and wasn't willing to accept.
So, he completely took over the responsibility of looking after those Magical Creatures, to which Cedric, the former "slave," was very happy.
"Something feels off."
"I think your feeling is correct, sir..."
"Alright, enough with the banter, get that thing out of there—"
William patted Dobby's head, indicating that he should get to work. As he spoke, he donned a lab coat and quickly headed towards the bottom of the Map Chamber.
"Ah... what's going on?"
Grindelwald, who was still circling the Secret Vault, looked up — he had maintained this for about a week — the air was filled with a sulfurous stench, which was somewhat unpleasant but not nauseating, while Nagini had already appeared in the center of the platform, imprisoned within a transparent field made of Rune Stones.
Of course, based on its recent behavior, it likely wouldn't run away.
It was a beautiful large snake, its emerald-green scales slightly mixed with black, faintly glowing under the light. At this moment, Nagini had already opened her eyes, her yellow snake eyes warily scanning the suddenly changing surroundings. The Anti-Apparition Array's Elf Magic could indeed be useful at times.
"I have some guesses — about how Voldemort came up with the idea to create a Living Soul Artifact, you know, that guy didn't actually know he turned Harry into one—"
William, rolling up his sleeves, explained to Grindelwald who had leaned in close, "Moreover, I can feel it, this creature is smart enough to understand what we're saying. Just like now, it's starting to space out, probably planning to play dumb to get through this 'ordeal'—"
Nagini: "..."
"So, need any help?"
"No, what's keeping you busy now is more important — I'll handle it myself."
Although William didn't activate his "Great Inventor" skill points, he wasn't a fool without knowledge. Since he already had some guesses, he naturally had some preliminary ideas about what he wanted to do. He waved his Magic Wand, and a thick book with a black beast hide cover flew down from the bookshelf leading to the ceiling.
"The Essence of Human Transfiguration"
Purchased from a stall in Gringotts for only two Sickles.
William's eyes glowed with a curious light as the hefty book spread open on the table. He quickly flipped through its pages, and after about two minutes, he finally lifted his head, "Dobby?" The House-Elf appeared behind him, "Bring over the Cauldron table from the Room of Requirement, including all the materials on it—"
Dobby disappeared on command, quickly reappearing with a heap of bottles and jars, efficiently placing everything on the stone table before stepping aside.
Meanwhile, William, taking advantage of this time, ran his fingertips swiftly over the slightly yellowed pages, eventually stopping at a passage of obscure descriptions. Next to it, a human shape gradually distorted, finally freezing in a certain beastly form illustrated.
"Blood Demon Curse... a maternally inherited curse, flows in the blood and soul, stripping away human nature, ultimately solidifying into a beast form..."
William frowned, coming to a conclusion — Kabuda being so intelligent was probably innate, after all, it's a male Niffler — but this snake... wait, how does one determine a snake's gender anyway?
"... Also, is the Blood Demon Curse irreversible?"
William's gaze fixed on the caged giant snake. Perhaps his gaze was too fervent, as Nagini instinctively shrank back, "I don't believe it." Saying this, William rubbed his hands, "First, I need to determine whether you are human—" He seized his Magic Wand.
"Reparo!"
Under normal circumstances, a Repairing Charm would not affect living beings, but now, the one casting the Charm was William—
"Hiss—"
Nagini let out a scream filled with unprecedented pain and shock, her massive snake body starting to thrash violently. Her form did not change as a result, William's Charm seeming only to cause her pain... or did it?
"It seems we've confirmed it."
Upon seeing this, William was invigorated, ceasing to use the Repairing Charm enhanced by Ancient Magic, already seated by the Cauldron table, waving his Magic Wand, causing various Magic Potion Materials to fly off the shelf and fall into the Cauldron—
Time flew by, and finally, after two days of careful experimentation by William, a Magic Potion radiating a soft golden glow appeared on the table.
"... Using Magic Potion as a primer, then supplementing with Dream Magic."
After staying up for two nights straight, William could not help but feel a bit dazed. Muttering to himself, he tossed the bottle into the Rune Stone field, and as if it had eyes, it immediately darted into Nagini's mouth the moment she hadn't reacted. The golden potion, upon entering her abdomen, then exploded with a roar—
"Hiss—!!"
This time, Nagini's scream was even more of agony, her massive body beginning to twitch violently, the emerald-green scales also undergoing change, their color seeming to gradually fade, while a faintly malicious red appeared above the scales. The red beams interlinked, finally forming a malicious chain pattern.
Blood Demon Curse.
Under the influence of the "magical elixir" concocted by William, this thing originally hidden in the bloodstream unexpectedly took form.