"So...?"
Harun said, looking at Kael standing in front of the stall.
More accurately, he was looking at the small figure standing beside Kael.
That figure was bundled up tightly from head to toe.
Clad in a worn hood, a black mask concealing their face, and oversized sleeves covering the backs of their hands.
On the outside, they didn't look much different from the street urchins commonly seen in the Underground Level. The problem was that Harun was not naive enough to fall for such a disguise.
"Did you pick up a kid while I wasn't looking?"
Kael did not answer.
"Hey."
Harun narrowed his eyes.
"Explain."
"Act like she isn't here."
"What?"
"Like she isn't here."
Saying so, Kael stepped inside the stall.
Rin watched Harun's reaction for a moment before cautiously following Kael inside.
Harun stared at the two with his mouth agape.
"Unbelievable."
A sigh slipped out on its own.
Harun had seen all sorts of people in the Underground Level, but this was the first time someone had clocked out, returned the next day with a bundled-up brat, and told him to act like she didn't exist.
"He really pulls all kinds of stunts."
Harun muttered under his breath as he pulled the shutter halfway up.
Business had to go on, after all.
***
Kael sat before the workbench inside the stall as usual.
Harun had piled up a mountain of items to repair since morning.
Small Magic Lamp stabilization modules, discarded security devices,
and miscellaneous parts of unknown purpose.
Kael picked up one of them.
He opened the black casing, exposing the circuit board.
After reading the flow of magic power and finding the blockage,
he scraped it clean, reconnected it, and secured it in place.
Vwooom.
Light came on in the first device.
Kael immediately picked up the second item.
Rin sat beside the workbench, watching him.
At first, she stayed quiet,
but as Kael began repairing the devices, that gradually changed.
Rin's gaze followed his fingertips.
Kael's hands were calm rather than fast. Above all, there was no hesitation.
Bzzzt.
The second device hummed to life.
Click.
The third device's locking mechanism released.
Vwooom.
A blue light lit up in the fourth Magic Lamp.
Without realizing it, Rin leaned forward.
Kael scraped away the charred section of the last circuit board and hooked a thin silver wire across the joint. Power instantly surged into the dead output terminal.
Watching from a distance, Harun grinned.
"That's our circuit tinker for you. Your hands are flying today."
"Be quiet."
"Look at your tone with your boss in front of a guest."
"Since when are you the boss?"
"It's my stall, isn't it?"
Kael didn't bother retorting and placed the repaired device on the cloth.
Just then, Rin asked very timidly.
"Um..."
Kael spoke without turning his head.
"What?"
Rin hesitated for a moment before speaking.
"Are you... a Magical Engineer?"
"A Magical Engineer?"
He pondered for a moment, then...
"Ah."
He gave a brief nod.
"You mean people who handle things like this?"
"Yeah."
"No."
It was a curt reply.
Rin stared at him blankly for a second.
"You're... not?"
"Yeah."
"Then how can you fix them so well?"
Kael picked up another device without answering her.
At his reaction, Rin pursed her lips slightly.
Her eyes narrowed ever so slightly.
She was pouting.
Kael noticed, but pretended not to.
Even so, Rin did not back down and asked again.
"Then... are you a Magician?"
Kael's hands stopped for the first time. Then, he slowly raised his head.
"A Magician?"
Rin shrank back slightly under his gaze.
"Y-yeah. Well... are you a Magician?"
Kael stared quietly at her. An edge had sharpened his gaze, which had been indifferent just moments ago.
Setting the device down on the workbench for a moment, he asked a question.
"Do you know about Magicians?"
Rin blinked as if caught off guard by the unexpected question.
"Uh... a little."
"A little."
Kael echoed the word.
Up until now, he had never seen a Magician of this world in person.
The concept of magic existed.
So did Magic Circuits... and magical engineering products.
But.
Beings who circulated magic power through circuits within their own bodies, deciphered spells, and twisted the laws of the world.
He had yet to see such a human.
Which was why he couldn't simply let Rin's words slide.
"Tell me."
Rin seemed a little startled by Kael's tone.
"About what...?"
"What you know about Magicians."
He looked straight into Rin's eyes.
"What kind of beings those called Magicians in this city are."
Rin parted her lips beneath the mask.
Hesitating for a moment, she carefully spoke up.
"In Magiterra, only people equipped with an Artificial Magic Circuit... that is, an ACU, can use magic."
Kael said nothing, but his gaze deepened.
Seeing his reaction, Rin continued.
"Circuits are divided from Tier 1 to Tier 9. The higher the ACU's number, the more complex spell formulas it can process, and the stronger the magic you can cast."
"Tiers..."
Kael muttered softly.
"But just having a high-tier circuit isn't enough. Since the brain has to process the formulas... if its computational processing capacity falls short, the person breaks down before the circuit can even hold up."
Rin fidgeted with her fingers.
"That's why there aren't many high-tier circuit users. It costs a lot of money, the compatibility rate is low, and if it fails..."
As her voice trailed off, Kael finished the sentence for her.
"They die, right?"
Rin gave a small nod at his words.
"Either die, or end up broken."
The Magicians of this city were not born, but manufactured.
The corner of Kael's mouth twisted.
"How interesting."
Rin asked cautiously.
"Inter... esting?"
"I mean it's dreadful."
"Ah."
Rin closed her mouth again.
Tapping the circuit board on the workbench with his fingertips, Kael continued his questions.
"Then do all those called Magicians in this city use devices called ACUs?"
Rin tilted her head as if thinking for a moment.
"Yeah... that's right. Probably?"
"Probably?"
"At least as far as I know."
Rin caught her breath softly beneath her mask.
While she still seemed to find it difficult to look directly at Kael, her tone was more relaxed than before.
"ACU stands for Artificial Circuit Unit. It's a device implanted into the body to take in magic power, and connected to the brain to calculate spell formulas."
Kael narrowed his eyes.
"So you mean it's not an external tool, but something inserted inside the body."
"Yeah. Usually, it's implanted in the spine, the back of the neck, or near the chest. I heard that the higher the tier, the closer to the brain it's connected."
"Sounds dangerous."
"Very dangerous."
Rin nodded.
"That's why not just anyone can do it. It costs a lot of money, requires a compatibility test, and needs a procedure permit. I heard plenty of people die after illegally implanting cheap circuits."
Kael looked down at the circuit board in silence, his fingertips slowly tracing the worn circuit lines.
"Implanting a Magic Circuit into the body, huh."
He muttered softly.
"It's more surprising that anyone survives doing something like that."
"Still, without an ACU, you can't use magic."
Seeing Rin take it for granted, Kael fell into thought for a moment.
If that was common knowledge in this city...
Kael slowly raised his head to look at Rin.
"Then are you using one too?"
Rin's hands froze.
"...What?"
"An ACU."
Kael asked, watching her reaction closely.
"I asked if you have one implanted in your body, too."
The color drained from Rin's face.
"N-no. I don't have anything like that."
"Is that so?"
"Yeah."
Rin nodded vigorously in denial, but...
"Hmm."
Kael saw right through the lie at once.
Yet he didn't press further and lowered his gaze back to the circuit board on the workbench.
"All right."
At that brief reply, Rin looked even more anxious.
"Do you... believe me?"
"You said you don't."
"..."
"That's enough for now."
Rin closed her mouth.
Just then, Harun's voice cut in from outside the stall.
"Both of you, watch your mouths."
At those words, Kael looked up.
"Do you think this is your bedroom?"
Harun said quietly.
"Why the hell are you having such dangerous conversations here?"
"Were you listening?"
"I might be old, but I'm not deaf."
Harun glanced around before pulling the tarp down a bit further.
"ACUs, Magicians... you don't go throwing those words around here."
"..."
Rin's shoulders flinched slightly.
However, Kael asked nonchalantly.
"Why?"
Harun looked at him dumbfounded.
"'Why,' you ask?"
"Yeah."
"Ha."
Harun put a cigarette between his lips, then pulled it back out.
"Sometimes you really don't seem like someone who's lived in the Underground Level for a whole year."
"I think I know as much as I need to."
"No. You only know what you care to know."
Harun leaned against the workbench and lowered his voice.
"In the Underground Level, the very concept of magic is faint."
"Even though magical engineering products are common?"
"That's completely different."
Harun pointed a finger at the broken devices on the workbench.
"These are objects. Things you can tear apart, fix, and sell when they break. But a Magician is a person. Someone with an ACU implanted in their body."
He paused for a moment.
"And there's hardly anyone like that down here."
As Kael listened in silence, Harun continued.
"Why do you think? Because it's expensive. Filthy expensive. Just a single low-tier ACU is worth more than the lives of hundreds of people in the Underground Level. A high-tier one? That goes without saying."
"Is it that much?"
"Is it that much, you ask?"
Harun chuckled.
"A single ACU is worth hundreds—no, thousands of lives in the Underground Level. I'm not exaggerating when I say circuits are more valuable than human lives."
Rin's hands quietly gripped her sleeves.
Harun added in a hushed tone.
"The Magicians who end up in the Underground Level are mostly low-tier. Tier 1 or Tier 2, rarely Tier 3. They're dropouts who became useless up top, got kicked out over debts, had their circuits ruined, or something like that."
"Where are they now?"
"Dead."
Harun answered without hesitation.
"At first, they all think they're something special just because they can spark some flames or erect a weak Barrier. But down here, those kinds of bastards stand out the most, you know?"
"Meaning they become targets."
"Exactly."
A brief silence settled inside the stall.
Rin kept her head down, and Kael tapped the circuit board on the workbench with his fingertips.
"So the word 'Magician' itself is dangerous."
"Glad you finally understand."
Harun glared at Kael.
"Especially you."
"Me?"
"Yeah, you."
Harun jerked his chin toward Kael's hands.
"You're already weird enough as it is. You read the flow of magic power without blueprints, and devices you've never even seen before power on with just a casual touch."
"It's not casual."
"Looks casual enough to me."
Harun bared his teeth.
"Add words like Magician or ACU to that, and these idiots will start letting their imaginations run wild. Wondering if there's something implanted inside your body, or if ripping you open will yield something valuable."
As Rin sucked in a breath, Harun glanced at her for a moment before lowering his voice even more.
"So keep your mouths shut."
"...Understood."
"Yeah. Please do."
Harun grumbled.
"Just stick to fixing things today. I don't feel like having my entire stall ransacked over some reckless talk."
Kael did not reply.
It was then.
A sudden commotion erupted outside the stall, making it seem like a fight had broken out, but...
"What is it?"
This time, that wasn't the case.
When Harun lifted the tarp slightly and peered outside, a crowd had gathered in one of the market passageways.
Frowning, he poked his body out of the tarp.
"Hey."
He grabbed the arm of a passing man.
The man tried to pull his arm away, but stopped once he saw Harun's face.
"What's going on? Why all the racket?"
"You don't know?"
"Would I be asking if I did?"
The man glanced around once and lowered his voice.
His voice was tinged with both excitement and fear.
"People came down from the upper sector."
At his words, Harun's expression hardened.
"What?"
"Folks from the upper sector. Guys in suits. The Security Force is with them, too."
"The Public Security Bureau?"
"No. Not the Public Security Bureau."
The man swallowed hard.
"It's the corporations."