Harry rubbed his still somewhat dazed eyes and sat down on one side of the compartment, feeling a bit distracted.
"Click—"
"Tell me, what did you just do?"
Fastening the latch of his suitcase, William turned around and looked at Harry. At this moment, the compartment was occupied only by him and Harry, as Lupin was outside handing out chocolate and hot cocoa, considering the less-than-pleasant physical impact brought by the Dementor ProMax to those little wizards, even William was initially affected.
But his strong and unreasonable emotion magic quickly helped him adjust his emotions.
In short, to prevent anyone from feeling hopeless about life after a brief period of isolation and emo, directly jumping off the train, Lupin started knocking on doors to provide warmth.
And of course, William didn't follow. Compared to eating chocolate, he was now more interested in the boy before him—looking at the slightly yellow-green flame above Harry's head, he nodded, "Hmm, it seems like the quality of the potion you made is still up to standard—your grades in Potions Class should be good... okay, pretend I didn't say that."
After missing one summer, he almost forgot the demeanor of a certain unnamed Potions Class professor, William waved his hand.
"I... yes, thank you for your potion recipe."
Harry's tone was somewhat uneasy. He lowered his head, the flame on his head gently swayed.
"No need for unnecessary courtesy—let's talk about this first. I heard you shot your aunt onto the wall?"
William waved his hand, signaling the other to directly cut to the chase, and at this moment, a muffled whistle sounded—the Hogwarts Express started again.
"It was Aunt Marge who first..."
Hearing William's question, Harry's heart tightened suddenly. Although he sensed a strange tone from the other side, he still instinctively wanted to explain, but was interrupted by William again. Under silent gaze, the boy could only choose to nod quietly.
"You used magic—I mean, not because of your emotional fluctuation, but because you drew your magic wand?"
"...Hmm."
"Why? You shouldn't be someone who loses their temper—"
William furrowed his brow, according to his understanding of the boy, Harry shouldn't have done this—after all, in order to train the other's soul and mental strength, he had conducted various forms of training and challenging for Harry in the first half of the year, and later even assessed that his mental strength was up to standard.
Logically, the soul from young Voldemort, Little Tom should have been completely assimilated by Harry.
But... seeing the blazing green flame above the boy's head, William couldn't help but click his tongue, it seemed the situation had quite a discrepancy with his expectations.
...Interesting.
"I... there was a voice in my mind at that time, it told me to teach her a lesson..."
Harry's tone was somewhat hesitant, but William didn't need him to say the next half of the sentence, it was clear who needed a lesson—it could even be said that Harry almost took this step because according to Harry's subsequent descriptions, it included him forcibly suppressing the thought of changing his attack spell.
"...At that time, I seemed to want to use a kind of black magic."
The boy lowered his head to look at his hands, a strong sense of doubt in his tone—he doubted his own feelings, after all, he was only in his third year, let alone black magic, he hadn't mastered many offensive spells, of which the most familiar was still the "Disarming Spell" taught by William in the Duel Club.
So, logically, he shouldn't be able to use black magic at all.
But... in William's eyes, this seemed perfectly normal. Harry indeed didn't know black magic, but that doesn't mean Little Tom didn't! Or rather, who in the world had a deeper knowledge of dark arts than Little Tom?
Anyway, William had always believed that his magical creativity and perception were not as good as people like Dumbledore and Voldemort.
He just took advantage of Ancient Magic—although this "advantage" was often strong enough to be outrageous.
"Then, what about just now?"
William nodded, not dwelling on this issue for long, but instead changed the subject.
"...More or less, that voice appeared again, it told me to cast a charm at that..."
"Dementor."
"...Oh, cast a charm at the Dementor, so I did."
Harry pursed his lips, once again opting to downplay the seriousness of the issue, seemingly reluctant for William to view him as a bad person, he continued.
"Just a regular charm?"
"Probably?"
"Try casting it at me again—"
With William's words, a purple barrier slowly raised around him.
"Ex…Expelliarmus! (Disarming Spell)"
Under William's serious gaze, Harry took a deep breath, then swung his wand, the deep red spell collided with the same-colored Iron Armor Spell, causing a ripple that wasn't weak. Staring at the location of the ripple, William's pupils slightly flickered with a trace of blue light—
Although the charm was different from the previous one, that wasn't the key issue because William had already felt the power contained within Harry's charm.
But there was no space for experimentation here—
William furrowed his brow, the next moment, a knock sounded, Lupin's voice came from outside the door, "Can I come in now?"
"...Of course."
William said while opening the compartment door, welcoming Lupin who was carrying a shoulder bag inside, "Would you like some more chocolate?" Lupin reached into the bag and grabbed a bunch of Chocolate Frogs. These were all procured from the train conductor, because compared to profit, the mental and physical health of students was obviously more important.
"No, thank you..."
Harry shook his head, clearly not in the mood at this moment, the boy's gaze was still firmly fixed on William—but it was apparent the latter didn't plan on giving him a quick answer, after all, many things still required extra verification, guesses were merely guesses.
"Maybe you'd prefer to be with your friends right now?"
William shook his head, containing a clear meaning in his words, and under his candid dismissal, Harry, though disappointed, still habitually nodded, then got up and headed towards the compartment door, not forgetting to help the two close the door.
"So... what's the actual situation?"
Lupin popped a piece of chocolate into his mouth, stared at the tightly closed compartment door in silence for a moment, finally exhaled and leaned back in the seat, "Does Harry have a physical problem?"
While asking this assumption, Lupin's expression seemed a bit tense.
"No... things are a bit complicated."
William scratched his head, his fingers unconsciously tapping on the suitcase—he hadn't actually noticed the peculiar behavior of the Dementor at first, after all he had just had the idea of capturing a Dementor for an experiment, then not even a few hours later one was delivered up to him, honestly, William felt as though he'd be sorry to say no to the Ministry of Magic.
So, from the time Harry started taking action, to when Lupin started to fall behind in the confrontation, William had actually been busy... making preparations for restraining the Dementor, after all, this was a non-physical entity, different from Boggarts which liked to hide in cupboards, Dementors were highly aggressive.
Therefore, its containment unit needed to be sufficiently capable of isolating its influence.
Meanwhile, in reality, Lupin's gaze also began to lower along with William's actions, when he saw the suitcase, his expression faltered, "So—if the Ministry of Magic asks about the missing Dementor on the train, how should we explain?"