"Squeak squeak!"
Just as William continued explaining, Kabuda, who had searched every pocket on his wizard robe, poked its head out from the hood. Initially, it instinctively shrank back from the Dementor's aura, then as if seeking praise, it handed over a glowing monocle to William's ear—
Harry, upon hearing the sound, instinctively looked up and saw a gold-rimmed black lens being held in Kabuda's claw. Yes, it was clearly a monocle, but the lens was a faint glowing shade of black.
Perhaps it was a trick of the light, but when Harry first glimpsed the monocle, he thought he saw a flash of golden light. However, when he focused again, the unobtrusive golden glow had vanished without a trace.
A single-lens sunglasses?
Looking at the odd item in his hand, William couldn't help but sigh—but there was no choice; the larger Seik crystal still required further investigation, and he wasn't planning to cut that item for a while. Hence, he could only use the small piece acquired in Austria for some experiments, as the small stone couldn't be fashioned into two lenses.
So, he ended up making a single-lens sunglasses of sorts as an improvised solution.
Primarily, since returning to Britain from Egypt, he discovered a capability of the Seik crystal: when his vision passed through this semi-transparent stone, it allowed him to see magic traces that he typically wouldn't notice, magnifying many inconspicuous details infinitely—
And this groundbreaking scientific expansion was merely stashed away as a simple token by that poacher organization...
A waste of a treasured resource...
Retrieving his thoughts, William went back to looking at the monocle in his hand. After a brief hesitation, he placed the monocle over his left eye—for some reason, he felt putting it on the right eye might lead to some unfortunate event.
"Alright, now cast a spell towards that thing—use the curse you employed on the train."
With his lens secured, William wasted no time, stepped back a couple of paces to the side near the door, raised a finger towards the Dementor in the center of the room, signaling Harry to draw out his magic wand.
"...Okay."
Realizing William intended for him to cast a spell on the Dementor rather than subject him to hellish forced-feeding training, Harry breathed a sigh of relief, lifting his Holly Wand, and the blue charm flashed and vanished—
"Expulso. (Blast apart)"
"..."
No change occurred, similar to when William attempted it himself earlier. Although the dark blue charm reflected a solid foundation, upon passing through the Dementor, it failed to incite even the slightest ripple—
Hmm...
Still lacking controlled variables?
William furrowed his brow, gently marking a stroke in his notebook, then motioned for Harry to try again. Similarly, the blue charm struck the wall opposite the room, scattering wood chips that flew wildly. Fortunately, the Room of Requirement's self-healing capabilities were top-notch and reverted to its initial state almost immediately.
This method yielded no results...
William shook his head, indicated to a ready-to-continue Harry to stop, then furrowed his brow, his thoughts going back to the moment Harry cast the spell—facing the Dementor, same charm, same magic potion, and the wand hadn't changed...
So, where was the problem—
Then, as if coming to a realization, William's eyes sparkled subtly, and in the next instant, without any premonition, the cold despair unique to the Dementor returned abruptly, almost instantly evoking a sense of fatal suffocation in Harry—
"Cough cough—William!"
The boy instinctively shouted, but all that responded was abruptly darkened vision—the Dementor moved.
The Dementor that had devolved from a black robe to a mini-skirt hadn't lost much of its imposing aura, and the emotions of despair as vast as mountains and seas held no less impact for Harry. The boy stared helplessly, eyes wide, as hands the size of a newborn's emerged from beneath the "mini-skirt" and gently caressed Harry's cheeks...
"Ahhh!"
The piercing scream suddenly sounded near Harry's ear, and he awoke with a start. Following, a low, raspy voice, mingled with a touch of familiarity, softly whispered into his ear—
"Kill him!"
"Expulso! (Blast apart)"
The blue-violet charm erupted with a roar from the wand's tip, crashing heavily onto the Dementor's small face emerging from beneath the robe, barely pausing before shooting towards the opposite wall, leaving behind a massive crater—
But this time, the change in the Dementor was completely different from before, and a green flame suddenly ignited from the hem of its long robe, engulfing its entire figure almost instantly, and that cold despairing sensation disappeared without a trace...
Did I...solve it?
This was Harry's first thought that emerged in his mind, but immediately he denied it subconsciously, for this scene was too familiar and barring any mishap, the next moment, the Dementor should...
Just as Harry thought, the next moment, a vortex of green flames blazed suddenly into the air, gathering swiftly into a swirl, and a black robe far more powerful than before struggled to emerge from the vortex—the Dementor reappeared... it was indeed strengthened.
But this time, fear emotions barely had time to arise—
"Expecto Patronum! (Expecto Patronum)"
Smother at first sight!
The dazzling white light burst forth, and this time Harry didn't even react before feeling as if he was blind... No, just immediately overwhelmed by a cheering joyousness, and the negative emotion from the Dementor's touch on his cheeks completely vanished—was this heaven? No, could heaven truly be this delightful?
Truly variable control—
Seeing Harry influenced by his Guardian God, William didn't rush to remove the effect, but instead took off the monocle he'd been wearing over one eye, carefully wiping it—this was a valuable item that needed safekeeping.
Moments ago, when Harry unleashed the curse, William immediately noticed a foreign power within the boy.
Emotion Magic of love?
Impossible, that purely positive mother's love, how could it possibly bolster a curse's potency?
Hasn't Little Tom been fully assimilated yet?
No, that's not it; William was thoroughly familiar with Little Tom's aura, for they'd been intertwined for so long...
So, what exactly was that power?
…No, it's not right to figure it out now; the root issue wasn't all-important.
Currently, the most crucial matter is—ensuring Harry acquires Expecto Patronum as quickly as feasible!
Who knows if this strengthening has a limit? Hogwarts was teeming with Dementors and should things go awry, Harry alone might inadvertently encounter them, possibly leading to the emergence of a Dementor King directly enhanced! What if he doesn't anticipate this in advance? Wouldn't Hogwarts be drained dry?
You can't safeguard indefinitely from a thief—determined not to be inadvertently installed as a surveillance camera forcibly, William resolutely decided to expedite Harry's mastery of Expecto Patronum. Provided he grasped this defensive technique against Dementors, Harry wouldn't end up in a scenario where he's grasped by a Dementor for a gallic wet kiss…
…hopefully?