"They're assassins sent to kill me."
"...."
Assassins.
It had been quite a while since he heard such an ominous word.
No, actually, calling it an elegant term might be more fitting for the Underground Level. The bastards down here lived with the mindset that if they didn't like someone, one of them was simply going to drop dead.
Compared to that, calling someone an assassin was practically a noble title.
Kael looked at Rin for a moment.
The granddaughter of a high-ranking executive at Seraph Industry, currently hunted by assassins posing as bodyguards.
And the man in the black suit who had appeared before the stall earlier had drawn an unusual amount of attention.
'There's no doubt I've gotten tangled up in a troublesome situation.'
Yet at the same time, Kael's mind was already formulating a different move.
The original plan he had devised with Harun was to use the salvaged goods transport route. People couldn't go up, but these chunks of scrap metal could pass through, so the plan was to squeeze through that narrow gap and slip into the flow of salvaged goods heading for the Surface Level.
Even thinking about it now, it wasn't a bad plan at all.
Well... it was dangerous, unstable, and there was no telling where he would land. But at least there was a chance.
However, the situation had changed now.
The girl before him was connected to the upper echelon. By her own admission, she was the granddaughter of a high-ranking executive at Seraph Industry. While the possibility of false information couldn't be ruled out, seeing how frantically the other side was tearing through the area, it likely wasn't a lie.
If so....
Tap, tap.
Kael tapped the circuit board on the workbench with his fingertips.
"Rank."
Rin blinked.
"H-Huh?"
"Do you know your bodyguards' ranks?"
Kael looked at her, resting his chin on one hand.
"As their employer, you must have some information."
"...."
Rin clutched the edge of her mask with trembling hands, as if terrified.
"...The person who threatened you was Head of Security Pale."
"Pale."
"Yeah. Seraph Industry's Head of Security. He's 6th Rank, one of the few in the city."
"6th Rank, huh."
"Yeah. And most of the rest of his subordinates are probably 4th Rank. If they belong to the Security Office, they're at least that good. Some might even be 5th Rank."
"Hmm."
So that caliber was 6th Rank.
That was about all Kael thought of it.
He recalled Pale, whom he had faced outside the stall just moments ago. Since it was Kael's first time actually facing a Magician of this world, he had deliberately provoked him to extract as much information as possible.
He had handled plenty of magitech items inside Harun's shop.
He had seen crude auxiliary devices and illegally modified circuits used by lower-level laborers. However, seeing a Magician who properly operated an ACU—and one counted among the city's finest at the 6th Rank, no less—right before his eyes was a first.
Ultimately, he realized that while magic in this world was roughly similar to the laws of magic he used to wield, it carried a distinctly different texture.
Mana was maintained under constant pressure. In Pale's case, it had been refined so it wouldn't leak out, nor did it scatter excessively inside the circuits.
A structure where refined mana was taken in, the ACU organized the spell formula, and the user's nerves and equipment output the result outside the body.
In Kael's world, a Magician drew magic power into their body and circulated it. Much like naturally learning to breathe in and out without anyone having to teach you, wielding mana felt just like that to a Magician.
Yet here, the ACU replaced that role.
'Artificial.'
Even though he knew everything in Magiterra was artificially created, the artificial magic power he encountered for the first time came as quite a novel shock.
Kael pushed the cracked circuit board on the workbench with his fingertips.
"That's good information."
Rin lifted her head and looked at him in bewilderment.
"Good... information?"
"Yeah."
Without bothering to turn his head, Kael spoke calmly.
"Because now I know that level is 6th Rank."
Good prey to gauge just how strong the powerhouses of this world were. And an opponent he would soon have to settle things with anyway.
At least, that was how Kael saw it.
Rin stared at him for a long moment before asking cautiously.
"By the way... can I ask you one thing?"
"Go ahead."
"What did you throw outside earlier?"
Looking at Rin, Kael saw that she genuinely had no clue.
Right before Pale entered the stall, Kael had hurled a small piece of metal from the workbench out the window. Rin had seen it, but she clearly hadn't understood why he did such a thing.
Kael replied nonchalantly.
"A scrap of metal that absorbed your magic power."
"...?"
Rin's eyes went blank.
"My magic power?"
"More precisely, the lingering trace leaking from the circuits inside your body."
Kael picked up one of the broken circuit boards resting on the workbench.
"When you got scared earlier, your magic power wavered a bit. It was very faint, but enough that their gear could have picked it up."
At his words, Rin's face turned pale.
"Th-Then...."
"Yeah. Meaning you could've been caught even if you stayed hidden."
As Rin swallowed hard and barely managed to calm down, Kael set down the circuit board and continued.
"That's why I tossed out the piece of metal that held the strongest trace of your magic power."
"Why did you...?"
"As a decoy."
Kael pointed toward the outside of the stall.
"Because what they're looking for most likely isn't your body itself, but the unique wavelength emitted by your circuits. But if a scrap of metal coated only with that trace gets mixed into a junk pile, the detector confuses the reading between a person and an object."
Rin slowly parted her lips.
"Is that... even possible?"
"It is."
"How?"
"Because your magic power was attached to that metal."
"When did I ever...?"
At her words, he pointed toward her mask.
"The mask strap you touched."
Even as Rin hesitated and unconsciously fiddled with her mask, Kael calmly explained.
"I replaced the clasp inside your mask this morning. Perhaps because your circuit was unstable, the clasp absorbed the residual trace well. Since you pulled on it several times, it was only natural for your magic power to rub off on it."
Rin instinctively touched the strap of her mask.
"...Did you know I had an ACU implanted?"
"Yeah."
"Since when?"
"Since you first came into the room."
Rin stared at him as if struck speechless, but Kael merely shrugged as though it were nothing.
She was left speechless by his attitude for quite a while.
"Why go that far...?"
Kael looked at her nonchalantly, as if it were completely trivial, and spoke.
"We made a deal."
"...."
"I protect you. You give me knowledge."
Completely calm.
"I merely fulfilled my end of the contract just now. Nothing more, nothing less."
"...."
Kael picked up the circuit board on the workbench again and fell into thought for a moment.
The value of this deal was far greater than he had initially expected.
At first, he had only intended to hide Rin and obtain a bit of knowledge about the Surface Level. Upper-level lifestyles, transit procedures, citizenship management, corporate structure. He thought knowing just that much would be enough, but....
If he used her properly, he could steer the plan in a much better direction. Rin was undeniably more than just someone with knowledge of the upper level.
She could be called the key to reaching the interior of Seraph Industry... or at least the upper echelon.
He still considered the salvaged goods transport route he had planned with Harun to be viable, though.
That path was high-risk and high-reward. Even if he made it up, there was no telling where it connected, and getting caught in a single inspection could throw him straight into a waste compactor.
On the other hand, Rin was different. There were people pursuing her, people who wanted her dead.
That meant her very existence was significant enough to be a threat to someone.
'She's a target with that much value.'
For now, that was enough.
The problem was what came next.
Kael rolled the metal scrap on the workbench with his fingertips as he thought.
How to deal with those scum.
Pale, 6th Rank, Head of Security at Seraph Industry.
Combining the information Rin had given with the presence he had directly witnessed earlier, a rough outline had formed. But Kael had never liked acting on mere conjecture.
For he had learned from experience that the ones who lose their lives are usually the ones who believe themselves to be clever, whether they were humans or demons.
"Rin."
"Yeah?"
"Cast a basic spell."
Looking caught off guard, Rin asked Kael in return.
"Right now?"
"Yes."
"Here?"
"Yes."
As Rin looked around, flustered, Harun immediately scowled and barked at him.
"Hey. After all that chaos just now, you're going to make her use magic in here?"
"A small one."
"Small one or whatever, damn it...."
"It's a necessary step."
At that, Harun swallowed his curses and shut his mouth.
"Anything?"
"Anything."
"I'm... not very good at it."
"You don't need to be."
Kael nudged an empty metal cup on the workbench with his finger.
"Just move this cup."
Rin hesitated for a moment, then nodded.
She slowly raised her right hand.
Her fingertips trembled slightly, and the moment a tiny speck of blue light gathered at the tip of Rin's finger, the metal cup on the workbench rattled.
After nudging it about half a span to the side, Rin exhaled deeply.
"I-Is this enough?"
Without answering her question, Kael stared at Rin for a long moment, and then...
This time, Kael reached his hand out toward her.
Rin flinched, startled, but...
"Don't move."
With that single command, his fingertips moved past Rin's arm toward the nape of her neck.
Rin's body stiffened.
"Wh-What are you trying to...."
"Checking."
Kael brought his hand close to the skin beneath the nape of her neck, hidden by her collar.
A razor-thin distance, so close it was barely a hair's breadth from touching her skin.
At that moment.
"...."
He narrowed his eyes.
Yet at the same time, the corner of his lips began to curl up.
'The Magic Circuit reacted.'
The circuit that had dried up from the backlash of the detonation formula unleashed at the Demon King's Castle, remaining virtually unresponsive for over a year.