"The black market naturally holds auctions as well. And anything that makes it onto the auction floor is something you almost never see under normal circumstances.
"At the very least, the items' tiers are on a completely different level—things you simply cannot find anywhere else in the black market.
"If you're looking to buy yokai serum, sir, then the auction is exactly where you should be. Forget C-rank serum—even A-rank yokai serum may appear at the auction."
Black One's words genuinely caught Ren Kuroda's interest.
A-rank yokai serum was already the strongest type humanity was currently capable of producing. For an underground auction to be able to acquire something like that meant its overall caliber was exceptionally high.
After Ren and the others followed Black One away, the black market—once frozen in tense silence—quickly returned to its usual noisy bustle.
None of the black market merchants had expected this outcome. They'd all been certain a massive battle was about to erupt… only for the situation to be resolved in such an unexpected way.
The mysterious and powerful black market administrators had actually chosen to compromise with a young man—and had even taken the initiative to curry favor with him.
As for the Blood Leopard who had died earlier?
Sorry—everyone had already completely forgotten who that guy even was.
"Miss Black One, since it's an auction… I'm a bit worried that the funds I have on hand might be insufficient."
Because Ren frequently traveled between different worlds, he rarely had any use for money. He possessed plenty of currency from other worlds—but as for yen, he truly didn't have much.
On top of that, his mother, Amanoin Yasumi, was a notorious money-grubber. Nearly every paycheck Ren earned would be snatched away before it even had time to cool down, taken by his mother under one excuse or another.
"There's no need to worry about that," Black One replied smoothly."If Lord Ren takes a liking to any item, the black market can bid on your behalf.
"As for the funds—I don't believe someone of your strength would ever default on a debt. I, Black One, would also be more than willing to make a friend like you."
Black One had been pondering how to please Ren in the first place. Upon hearing his concern, she immediately offered what was essentially an interest-free loan from the black market.
"No, no—that's not what I meant," Ren said, shaking his head."Since it is an auction, I was wondering… could I also entrust Miss Black One with auctioning off a few items for me?"
To be honest, Ren possessed quite a lot of things. While most of them couldn't exactly be brought into the light, there were still items he didn't need and could reasonably sell.
For example, in the world of KonoSuba, he'd acquired a fair number of magic tools and recovery potions.
Magic tools were troublesome—the power systems were different, and adapting them would be a headache. But recovery potions, on the other hand, were absolutely sellable.
And besides the potions, he also had two bottles of A-rank yokai serum that he'd received as a reward from the Countermeasures Division after repelling the Hundred Night Demons.
Then there was also the item that could directly enhance spiritual power—the Low-Grade Spiritual Power Crystal.
As for why Ren didn't use the A-rank yokai serum to help Yuina Yako, there were two reasons.First, Yuina might not even accept something that precious.Second—and more importantly—Ren was worried that Yuina's sister's body simply wouldn't be able to withstand the corrosive effects of A-rank yokai serum.
Higher-grade yokai serum wasn't automatically better for everyone.
The stronger the serum, the higher the demands it placed on one's willpower and physical constitution.
Only a sufficiently strong will could resist the negative emotions carried within the yokai blood—and prevent berserk states or corruption.
From Yuina's earlier description, Ren knew her sister was practically in a semi-comatose state. Giving someone like that A-rank yokai serum wouldn't be saving her—it would be sentencing her to death.
At first, when Black One heard that Ren wanted to auction off some items, her expression turned slightly awkward.
She honestly thought Ren didn't even have C-rank yokai serum—what valuable items could he possibly have?
Anything eligible for the auction was either extremely rare or of a very high tier. If Ren brought out something too mediocre, it would drag down the auction's overall prestige.
But since Black One genuinely wanted to be on good terms with him, she didn't know how to refuse outright.
"Lord Ren, as for funding, we can simply lend it to you, so there's really no need for you to—"
She had intended to gently decline his request.
But the moment she saw the first item Ren took out, her words got stuck in her throat.
Because with her experience hosting countless auctions, she could tell at a glance—
The two yellow vials Ren casually pulled from his coat were yokai serum.
Blue yokai serum was C-rank.Yellow yokai serum, however, was undeniably A-rank.
And judging by the color alone, these weren't even the weakest A-rank variants.
The underground auction had sold A-rank yokai serum before, so Black One recognized it instantly.
At that moment, the way she looked at Ren changed completely.
She'd previously assumed he was broke—someone who had to come to the black market just to buy C-rank serum.
Turns out it wasn't that he couldn't afford C-rank…
It was that he didn't even bother looking at it.
It was like pulling out a wallet stuffed entirely with ten-thousand-yen bills, only to realize there wasn't a single hundred-yen coin inside.
The clown… was her.
After Ren calmly produced two bottles of A-rank yokai serum, Black One's attitude toward him underwent a total transformation.
Even for their underground auction, A-rank serum didn't appear every time.
And what shocked her even more was that the items Ren took out after the serum were, in her eyes, just as rare and valuable.
The so-called recovery potions could be set aside for now—after all, many shrine maidens and ritualists possessed healing abilities.
But the Low-Grade Spiritual Power Crystal…
The effects Ren described made Black One feel almost delirious with excitement.
She even had a strong premonition—
If this item appeared at the auction, it would trigger an absolute frenzy, one no less intense than when yokai serum had first been introduced.
According to Ren, this "Low-Grade Spiritual Power Crystal" could increase a user's spiritual power without any side effects.
The enhancement was permanent.There was no potential drain. No backlash.
Wasn't this the ultimate blessing for exorcists?
Everyone knew that an exorcist's spiritual power could only be cultivated gradually. Differences in talent and cultivation methods were what widened the gap between individuals.
Occasionally, someone might experience a breakthrough through sudden enlightenment—but that was something you couldn't force.
Black One had never heard of spiritual power being rapidly increased through any other means.
If this "Low-Grade Spiritual Power Crystal" truly worked…
Then the status of exorcists would skyrocket once more.
And compared to yokai—who grew stronger far more quickly—exorcists would no longer be constantly suppressed.
"Uh… I get why you're excited," Ren said, cutting in as he looked at Black One's ecstatic expression."But there's something I should clarify.
"While the Low-Grade Spiritual Power Crystal can boost spiritual power without side effects, its upper limit is only around A-rank.
"And the stronger someone's spiritual power already is, the weaker the effect becomes. On top of that, I only have a limited quantity—it was obtained purely by chance.
"So if you're hoping to mass-produce it like yokai serum… you might as well give up."
Ren's words immediately shattered Black One's beautiful fantasy.
While it was true that Ren could exchange these crystals endlessly—and each one only cost a hundred reputation points—raising an ordinary person's spiritual power from zero to A-rank would require an enormous quantity.
His reputation points didn't grow on trees.
He had no intention of letting massive amounts of spiritual power crystals flood the market.
Scarcity created value.
And regardless of whether such crystals existed elsewhere in this world, at least for now—he was the only one who had them.
After hearing Ren's explanation, Black One's excitement cooled significantly. Still, as she looked at the blue crystal in her hand, she didn't believe he was lying.
Judging from its structure, it clearly looked naturally formed rather than artificially manufactured.
And if someone could really create something like this, it would have entered the market long ago.
"Lord Ren, thank you for placing your trust in our underground auction," Black One said solemnly."Rest assured—I believe these items will fetch prices that fully satisfy you."
Earlier, Black One had wanted to befriend Ren purely because of his remarkable strength.
But after seeing the Spiritual Power Crystal, she realized just how wise that decision truly was.
With Ren's auction items in hand, Black One went off to prepare and preside over the auction. As for Ren and Yuina Yako, they used her connections to secure two seats inside.
This underground auction only took place once a month—and participation wasn't open to just anyone.
Either you had to possess considerable status, or you had to demonstrate outstanding strength or wealth.
Otherwise, you didn't even qualify to step inside.
Once inside the auction hall, Ren deliberately scanned his surroundings.
Most of the attendees were either heirs of major families or heads of exorcist clans.
Naturally, powerful financial conglomerates and exorcist organizations were also present.
Though it was called an underground auction, even the authorities—fully aware of the black market's existence—could only turn a blind eye.
The web of forces involved was simply too vast.
Some attendees concealed their identities with masks that hid both aura and appearance. Others showed their true faces without the slightest concern.
As Ren surveyed the room, he unexpectedly spotted a familiar face—
His colleague and friend, Kujo Hinano.
She was wearing an elegant evening gown that perfectly accentuated her voluptuous figure.
And standing beside her was a middle-aged man in a sharp suit.