The room above the Leaky Cauldron was better than Gavin had imagined.
At least it didn't have the musty smell he'd expected.
It was small but clean, with a wooden bed, a desk, a wardrobe, and a little window overlooking a corner of Diagon Alley. The frame was old, but the glass had been polished until it shone, reflecting the room's faint lamplight at night.
"Not bad."
Gavin set down what he was carrying and gave his verdict. "Better than riding the Knight Bus, at least."
He laid his new textbooks, quill, ink, cauldron, and wand on the desk one by one.
He'd taken in a lot that day.
Wands, Goblins, wizarding currency, Diagon Alley—and a wand that had unexpectedly interacted with his meditation practice in a remarkable way.
Meditation was what the West called it. In the East, it was generally known as introspection, Zen practice, or quiet sitting.
In the West, meditation was more a tool for mental training. In the East, it was a path to spiritual cultivation and immortality.
In Gavin's previous life, Silicon Valley and American academia had placed great importance on stress management. Daily exercise and meditation had become a trend. Oddly enough, a practice born in the East had flourished and developed even further across the ocean.
Hoping to improve his meditation, Gavin had once returned to his home country specifically to visit major Taoist temples and Buddhist retreats. He'd done a "little" research into the methods of various schools.
After crossing into this world, Gavin had kept up his meditation habit. He didn't know whether it was because this body was young or because of what he'd carried over from his previous life, but his progress had been astonishingly fast.
He wasn't sure what stage he'd reached. He was certain he hadn't grown an inner core or a nascent soul, nor had he seen the legendary inner landscape. But he could control his emotions with ease and examine himself from a detached, third-person perspective, calmly watching the "me" that kept generating stray thoughts as though he were an audience member.
"Does that count as the id, philosophically speaking?" Gavin wondered.
The side effects were exceptionally strong concentration, emotional control, and command of his thoughts.
If only I had a stats panel. Gavin felt those abilities couldn't be far from maxed out.
"Magic exists. That much is confirmed."
He sat at the desk, tapping his fingers lightly against its surface as he settled into thought.
"So there's only one question left."
"What exactly is it?"
He'd been thinking about that ever since the letter from Hogwarts arrived.
Why did magic exist?
What sustained it?
How could it affect the physical world yet leave no sufficiently clear trace in Muggle physics?
If it truly existed, it had to follow some kind of rules.
No matter how mysterious something was, if it acted consistently on reality, it couldn't be entirely beyond rules.
With those questions in mind, he opened The Standard Book of Spells, Grade 1 first.
The first-year textbook wasn't particularly thick.
By ordinary student standards, it was even approachable. It covered incantations, pronunciation, wand movements, basic explanations, and a few simple examples.
Gavin skimmed through it quickly.
He wasn't trying to learn yet. He was identifying the elements required to cast magic.
"Wand movements must be precise."
"Keep your emotions steady."
"Maintain a clear intention."
"Pronounce the incantation correctly..."
After finishing the book, he returned to the page on Lumos and stopped.
"So magic seems to require at least a few essential elements."
He summed them up under his breath.
"An incantation, a movement, a wand, and—the caster, including their will and emotions."
The first three were easy enough to understand.
But the last was what interested him most.
What exactly did the caster provide?
Energy?
Mental power?
Some special organ?
Or something else?
He closed the book and picked up his new wand.
Black walnut wood, dragon heartstring, eleven and a quarter inches.
It felt good in his hand.
"Let's start with the simplest one."
Gavin stood and switched off the light.
Click.
The room fell dim, lit only by scattered lights in the distance beyond his window in Diagon Alley.
He raised his wand and pointed it ahead.
He recalled the movement and pronunciation from the textbook.
Then he spoke.
"Lumos."
Nothing happened at the wand tip.
"Good."
Gavin nodded.
"That failed."
He wasn't surprised.
Success on the first try would have been strange.
"What went wrong?"
Rather than immediately trying again, he thought back to how that moment had felt.
The movement had been right.
The pronunciation should have been right too.
His intention had been clear.
That left only one possible source of the difference—
The wizard himself? His emotions? His will?
"I want it to light up."
"But wanting it doesn't seem to be enough."
He raised his wand again and closed his eyes. As he did when meditating, he first steadied his breathing.
Years of meditation had made him far more sensitive to subtle changes in his body than most people.
Gradually, he heard his heartbeat and breathing, felt his muscles contract and his blood flow. Faint, elusive thoughts in his mind grew clearer with each breath.
"Again."
"Lumos."
This time, a faint light flickered at the wand tip.
It was like someone striking the tiniest spark in the dark. It vanished in an instant.
At the same time, Gavin caught a change in his body. Something had felt different from usual.
"There it is."
He'd caught hold of something. Now he needed to amplify the sensation.
"Keep going."
"Lumos."
A soft white light bloomed steadily from the wand tip.
It wasn't especially bright, but it was enough to illuminate the entire room and Gavin's face.
He stood there, staring at the light for quite a while.
"Okay, it worked!" Gavin was delighted. He wouldn't need to carry a flashlight anymore.
Once his excitement had slowly faded, Gavin tried to recall exactly what had happened inside his body when the spell succeeded.
"Not the heart."
He ruled out one possibility first.
"Not the abdomen either. Definitely not the dantian."
He'd read so many fantasy stories about cultivation in his previous life that, when he finally encountered a supernatural power himself, he had naturally considered those possibilities.
Unfortunately, his body gave him no reason to believe them.
The change had actually occurred in his head.
More precisely—
In his brain.
"At the instant I cast the spell, it was as if something was being drawn into action."
Gavin turned the light back on, walked slowly to the desk, picked up his quill, and wrote the first line on a sheet of paper:
[Hypothesized source of magic: the brain]
After writing that, he paused, then continued.
[Spellcasting does not simply expend emotion or physical strength]
[It seems to use incantations, movements, and a wand to draw out a power already present deep within the mind]
He set down the quill and raised his wand again.
"Lumos."
This time, he wanted to sense the exact moment the spell took effect more clearly and try to sustain it for longer.
With a successful attempt behind him, the sensation of the spell taking hold was much more obvious.
It was a strange feeling of being "drawn."
As if something that had lain quietly deep inside his brain had been pulled out, just a trace of it, by the incantation and his intent. The wand then channeled it into the outside world.
The whole process was extremely fast.
But Gavin still caught it easily.
"Just as I thought."
He spoke softly.
"It's the brain."
The lamplight fell across the side of his face, revealing the delight of a child who'd discovered a new toy.
"No wonder a wizard's magic grows so noticeably during childhood, then levels off in adulthood..."
He kept writing as he thought.
[Known information from the original story: a wizard's magic strengthens with age during childhood, then stabilizes in adulthood]
[Hypothesis: linked to brain development]
[Question: if brain development is linked to magic, why is a wizard's upper limit fixed in adulthood?]
At that, he stopped writing and frowned.
"That's strange."
According to modern medicine's understanding of brain development, the human brain didn't stop changing completely at eighteen. Many regions continued maturing into a person's twenties.
If magic was closely tied to brain development, the pattern of a wizard's magical growth might not be so simple.
Unless—
A wizard's brain was different from a Muggle's to begin with.
[New hypothesis: wizards and Muggles differ at the organ level]
[To be verified]
Gavin looked at the words on the paper and breathed out softly.
"Now that's interesting."
If his hypothesis held, magic wasn't simply a "gift."
It was a difference in physiology.
In other words—
Wizards might be a different kind of human.
At least where one crucial organ was concerned.
That thought sent his mind racing further.
If magic could affect reality, then it had to be a form of energy, a force, or a field that Muggle physics had yet to account for.
Otherwise, there was no explaining how it could make a feather float, create light out of nowhere, or change an object's shape.
"A Fifth Fundamental Force?"
He murmured the phrase, then wrote another line on the paper:
[Conjecture: magic may be a form of fundamental interaction not yet discovered by Muggle science]
He decided that was too broad and added another line:
[Provisional name: Fifth Fundamental Force]
He glanced at what he'd written and couldn't help laughing.
"Could it be? A Fifth Fundamental Force? Or a higher-dimensional manifestation of the four fundamental forces?"
The page on the desk grew more and more crowded.
The faster Gavin wrote, the more questions he had.
[Wand function: amplify, stabilize, and regulate output]
[Incantation: establishes a fixed invocation pattern] [Movement: helps construct a stable casting pathway] [Emotion/will: affects the resulting output]
As he wrote this, another question occurred to him.
If a wand was an amplifier.
If casting spells was, at its core, drawing on magic deep within the brain.
Did that mean—
If magic itself was powerful enough, could it be released without relying on a wand?
Wandless Magic?
Another word came to mind.
Or rather, an Obscurus?
In the original story, an Obscurus was often described as a dark parasitic force formed by suppressing magic.
Its host was usually very young, intensely emotional, unable to control their magic, and extremely dangerous.
Most Obscurials did not live long.
"Suppressing it..."
Gavin repeated the words under his breath.
Then his eyes narrowed.
"In other words, magic should naturally disperse, release, and flow."
"But if it isn't released for a long time, it might build up in a more primitive, higher-pressure state."
He picked up his pen and wrote several new lines. This time, he pressed noticeably harder.
[If the compression process could be controlled, could it produce denser magic?] [Problem: how to prevent the host's death?]
He paused.
Then he added one more line:
[Perhaps it would require a stronger body, a more stable mind, and a controllable outlet]
After writing that, even Gavin fell silent for two seconds.
"It's only the first day."
He looked at the page packed with notes and muttered to himself.
"Am I getting a little ahead of myself?"
Night deepened outside.
Faint voices still drifted up from the Leaky Cauldron below, along with clinking glasses and the odd laugh of someone who had drunk too much.
But the room was quiet.
So quiet that all he could hear was the scratch of his pen across the paper.
Gavin reorganized his earlier thoughts.
Then he added a few lines at the bottom.
[Further research] [1. The relationship between magic and the brain] [2. How a wand works as a regulator] [3. Feasibility of Wandless Magic] [4. Magic compression and the Obscurus] [5. Can spells be reverse-engineered?]
With that done, he finally set down his pen and rubbed his brow.
Only then did he feel a little tired.
It was the fatigue that came after intense mental effort. He had not pushed this new brain so hard in a long time.
"So casting spells really does take mental effort."
He jotted that down as well.
Then he prepared to lower his wand and end his final casting of Lumos.
But at that very moment, he stopped.
"Wait."
He studied the gentle white light at the wand's tip, lost in thought.
"Lumos itself seems to make me feel a little calmer."
The sensation was subtle.
But he was sure of it.
As he watched the soft white glow from his wand, his mind, slightly worn out from all that thinking, did seem to ease.
Someone less attuned to their physical and mental state might never have noticed.
[Addendum: Lumos may have a mild, positive stabilizing effect on emotions] [To be verified]
After noting that, he finally waved his wand and extinguished the light.
The room went dark again.
Only the distant lights of Diagon Alley beyond the window faintly outlined the pile of papers on his desk.
Gavin lay down on the bed but did not fall asleep at once.
His mind was still turning things over.
Magic.
The brain.
The Obscurus.
The Fifth Fundamental Force.
Each word was like a door.
And he had only just pushed the first one open a crack.
"Hogwarts..."
He stared at the ceiling in the dark and spoke softly.
"I hope you don't disappoint me."
Before long, Gavin deliberately drew his wandering thoughts back in, and his breathing gradually slowed.
He drifted off to sleep.
On the desk, a night breeze slipping through the window stirred one corner of the page covered in his research theories.
In the faint moonlight, the top line was just visible:
[The Fifth Fundamental Force: magic?]
Before you continue