"...'Boom'?"
William repeated Grindelwald's vivid gesture, raising his eyebrows high, "So, according to your explanation, if Muggles follow the process you just described, there's a high probability they would explode directly? Like a Flobberworm stuffed full of dung bombs?"
"Uh, yes, but why is your analogy so disgusting?"
Grindelwald nodded, but William's vivid analogy made him frown involuntarily.
"...Because someone did it right in front of me."
William patted his forehead, and two identical redheads appeared in his mind's eye—yes, only the Weasley twins could do something like that.
"I really didn't expect you to care so much about this kind of thing—"
William crossed his arms, gently tapping his fingers on his arm, "If I remember correctly, you were a complete racist before. What was it your followers believed in? Enslaving all Muggles? If you keep researching, you'll be handing the Muggles the weapon yourself—"
"Perhaps this is the price of scientific progress—"
Grindelwald clasped his hands behind his back, tilting his head at a forty-five-degree angle to look at the ceiling, "Which revolutionary invention didn't require sacrifice and compromise? After being confined for half a century, I've come to understand many things—and besides, the rise of Muggles can no longer be restricted. With just a metal shell, they killed tens of thousands of people—"
"That thing's called a nuclear bomb. The Secret Vaults could easily achieve the same effect if detonated—"
"But the Secret Vaults are non-replicable, while Muggles'...what's-it-called can be mass-produced..."
"...Who says it's not replicable?"
"?"
William's soft whisper seemed ordinary, but it made Grindelwald's spine tingle with light. The old man opened his eyes wide, his few teeth spread in a wide grin, "You, what did you say?" He stared at William's emotionless face, seemingly hoping to see a smile.
But unfortunately, William remained expressionless, "Although I'm not great at invention, I have a strong learning ability—I saw the entire process by which Isadora Morgana created this thing in their memory." William raised his hand, pointing to the four murals in the corner of the Map Chamber.
Ever since Grindelwald moved in here, those guys have rarely shown up.
"..."
"Don't worry, I currently have no intention of draining the emotions of all of Scotland, nor of losing my humanity."
"..."
Grindelwald wasn't sure what expression to show, should he praise William's "honesty"? He would rather the other person say this was just a joke, "More than once, I've thought you're more like... a Dark Lord than myself or even Riddle."
"That title sounds awful."
"...Indeed."
"But it's good that you can still think so now."
William, known as the Realms of Magic's Oppenheimer Richard, patted the shoulder of the former Dark Lord next to him, "Old Bee truly has eyes that can see into people's hearts—but, I must say again, Mr. Filch's matter won't happen again—if I catch you conducting dangerous experiments on humans secretly... humph humph."
William didn't continue, but that onomatopoeia was evidently all he needed to express.
Grindelwald's face fell, muttering, "Wasting resources... stubborn... practically been assimilated by Dumbledore..."
"What did you say?"
"I said... I'll give you a heads-up next time."
Seemingly growing more like an "old child" with age, Grindelwald turned around sulkily, patting the glowing Secret Vault sphere hovering in mid-air with some regret, as if soothing a wronged child.
"You'll still need my approval."
William couldn't be bothered to continue bantering, turning his gaze back to Ares, the War God, whose arm had been removed on the table, "A wooden body... energy activation... tsk, sounds like some kind of advanced Magic Puppet—could the supposed 'awakening' of these old mummies mean emerging from stones and 'activating' these advanced figurines?"
"Very close to the essence."
Grindelwald nodded, "According to my preliminary research, these guys' souls are different from ordinary wizards; they're essentially highly condensed spiritual entities with specific imprints. Perhaps Helbo later derived the process of creating Soul Artifacts from this magic—and these puppet bodies were designed as vessels for these spiritual entities."
William nodded thoughtfully, "So, is it possible to drive these things using only energy, without infusing a soul?"
"Are you saying?"
"Currently, the 'part manufacturer' is in my hands, while my stone magic puppets suffer high wear from daily battles—you know, Seik Stones are very valuable."
"I see—"
Grindelwald nodded again, a knowing gleam in his eyes, "You want to go to war."
"...It's called being prepared."
William waved his hand, indicating, "You might not shoot, but you shouldn't be unarmed."
"I don't believe it."
"...Right, I actually just want to rule the world."
"That's more like it."
Grindelwald nodded solemnly, folding his arms, "I am willing to serve!"
William squinted, "Wait, have you been watching TV dramas recently? Was 'Romance of the Three Kingdoms' just airing this year?" He turned his head, searching the Map Chamber for a suspicious television-like object.
"Just joking."
Grindelwald shook his head, steering the conversation back on track, "Alright, what you say isn't impossible, but I'll need some time to study it, as for the samples—" he said, turning to look at Ares, who lay fragmented on the stone table behind him. The latter had long been sealed off from hearing by William, his head facing down, resembling a real puppet.
"He's yours, just don't break him."
William stretched, imitating Grindelwald's gesture to wave at the floating light sphere, which promptly descended.
"!"
"I told you, I'm a fast learner."
Seeing Grindelwald's shocked expression, William smiled in satisfaction, "As for Hera over there—" William paused, squinting, "Since the Celestial Empress wants a Secret Vault, we'll give her a Secret Vault—to catch a big fish, you need good bait—"
That was always William's style, with notable achievements like—
Catching Kabuda with Golden Galleons, catching Sirius with Peter Pettigrew, catching Voldemort with Harry, catching Dumbledore with Fawkes... and more.
Aiming to never return empty-handed (self-proclaimed)!