For a starting bid of 300 million yen, no one present found it strange. In fact, the moment the opening price was announced, the number was driven up to 500 million yen within just a few short minutes.
By this point, the only ones still calling bids were major zaibatsu magnates and members of exorcist families.
As for everyone else—despite their equally burning desire for an A-rank yokai serum—they were perfectly aware that all they could do was watch. The final hammer price for something like this was never going to be cheap.
The first A-rank yokai serum was ultimately sold for 1 billion yen, snapped up by a member of an exorcist family—and by pure coincidence, it was someone Ren Kuroda actually knew.
The eldest daughter of the Kagamori family.
She counted as Ren's senior from his days at the Onmyō Academy, and back when the Spider Princess and Nurikabe had been registered as shikigami, she had even tried to buy the Spider Princess outright.
Now, this young lady had long since graduated from the academy, and the spiritual power she radiated faintly placed her at the upper B-rank.
As a member of the Kagamori family, profits from holy water alone had already filled their coffers to overflowing. Everyone present knew they couldn't compete with her financially, and rather than offend the Kagamori family, they chose to bow out early.
As for the second serum, without the Kagamori heiress dominating the field, the bidding grew even fiercer. In the end, it was claimed by a Tokyo-based mega-conglomerate for a staggering 2 billion yen.
Just two A-rank yokai serums, and Ren had already earned 3 billion yen in total.
Even he couldn't help feeling stunned.
Thinking back now, he'd once believed the Non-Human Countermeasures Division was a pretty ethical organization. Looking at this, though? Black-hearted didn't even begin to cover it.
How much had he been paid for exterminating A-rank yokai back then?
And now two vials of serum alone had sold for 3 billion yen.
Of course, "yokai serum" hadn't even existed at the time—and that was before the chaos fully erupted.
Still, in hindsight, Ren felt a sharp pang of regret. All those times he'd exchanged the remains of defeated yokai for points…
That had been a massive loss.
Once the two A-rank serums were sold and the atmosphere in the hall reached a fever pitch, Kuroichi immediately struck while the iron was hot, producing yet another vial.
The moment Ren laid eyes on it, his interest was piqued.
There were three final auction items. Two of them belonged to him.
Which meant the vial in Kuroichi's hand was the one that didn't.
And if it was being auctioned after the A-rank yokai serums, then its value clearly wasn't inferior to them—
If anything, it might be even rarer.
"Everyone here knows that major research corporations are currently focused on developing yokai serums. Naturally, our black market is no exception.
"The vial in my hand is called a 'Serum Inhibitor.' It is an accidental byproduct that emerged during one of our research projects.
"Afterward, we conducted numerous experiments, but were never able to reproduce it. Therefore, the vial you see before you can be considered a one-of-a-kind artifact."
"As for its effects—it can significantly suppress the yokai corruption that occurs when consuming yokai serum, reducing the associated risks to the absolute minimum.
"The starting bid is also 300 million yen. Please bid freely."
The moment Kuroichi explained the vial's function, the crowd erupted once more.
To ordinary people, this item might be useless—but to anyone planning to use yokai serum, it was practically a treasure beyond price.
Everyone knew that consuming yokai serum carried the risk of being overtaken by yokai corruption. An agent capable of preventing that?
Its value spoke for itself.
And the black market's timing was clearly deliberate. By auctioning this vial after the A-rank serums, they were baiting those who had just bought one.
After all—wouldn't they be tempted now?
"Five hundred million yen."
The answer was obvious.
The instant she heard the Serum Inhibitor's effects, the Kagamori heiress raised the bid.
That single number instantly cooled the fervor of more than half the room.
It wasn't that the item wasn't good.
They simply couldn't afford it.
Most people would already have to sell everything they owned—and accept massive risk—just to buy a yokai serum. Where would they find the money for a Serum Inhibitor on top of that?
And owning an inhibitor without a serum was completely pointless. If you had that much money, wouldn't buying another A-rank serum be far better?
This Serum Inhibitor was undoubtedly a blessing—
But one only the wealthy could play with.
Besides, while the black market claimed it was currently a one-of-a-kind item, the fact that it existed at all meant mass production might be possible someday.
Why spend an outrageous sum now on a wildly overpriced "unique item," when you could wait until production stabilized and prices dropped?
They weren't in any rush.
For all these reasons, once the Kagamori heiress called out 500 million yen, the auction floor fell into an awkward silence.
This was clearly not what Kuroichi had hoped for.
She had deliberately placed the Serum Inhibitor after the A-rank serums to drive up its price—but the current situation was far from ideal.
"Five hundred million yen. Any higher bids?"
"As one of the administrators of the black market, I can assure you that this agent truly was an accidental creation. It has no side effects, and in the coming years, the technology required to reproduce it will definitely not mature."
Five hundred million yen was far below Kuroichi's expectations, so she could only add more emphasis.
But her behavior immediately drew the displeasure of the Kagamori heiress.
After all, she had deliberately jumped the price by 200 million yen to intimidate other bidders—and now Kuroichi was actively encouraging competition.
That was nothing but trouble for her.
"Six hundred million yen."
At last, just as silence lingered and Kuroichi was about to declare the item sold at five hundred million, a voice rang out from another direction.
Ren Kuroda had spoken.
His reason for bidding had nothing to do with Kuroichi's added explanation.
It was because—driven by curiosity—he had just used the System's Appraisal function on the vial.
Item Name: Serum InhibitorItem Rank: S+Item Description:A miraculous reagent created using multiple special yokai under highly unusual conditions.Capable of completely suppressing the corruption side effects of all yokai serums below S+ rank.For yokai serums above S+ rank, the suppression effect is weakened.
P.S.:An accidental creation born from the carelessness of a scientist, a flawless formula, and utterly unparalleled luck.The same miracle will almost certainly never occur again.
Ren was genuinely dumbfounded.
This thing was actually an S+-rank item.
When Kuroichi said it couldn't be reproduced, even they likely believed they were exaggerating.
Through repeated experiments, they had already identified the components of the Serum Inhibitor. In theory, as long as the ratios were correct, a second vial should be possible.
But Ren trusted the System's judgment.
If the System said the miracle could never happen again, then something unknown must have occurred during its creation—something no one else was aware of.
Even if the black market eventually developed a new Serum Inhibitor, its rank and effects would never compare to this one.
The reason it was being auctioned so cheaply was likely because there was nothing like it to use as a reference.
Not everyone had a cheat like Ren.
That's right.
For an S+-rank, irreplaceable, one-of-a-kind item, a starting bid of 300 million yen could only be described as dirt cheap.
There was no way Ren wouldn't fight for it.
"Eight hundred million yen!"
However, the moment Ren raised the bid to six hundred million, the Kagamori heiress glanced at him—and immediately added another two hundred million yen.
That price was already pushing close to her limit.
While the Kagamori family was wealthy, she was still not the head of the household, and the funds she could directly control were limited. She had also just spent 1 billion yen on an A-rank serum.
After calling out 800 million yen, she shot Ren a fierce glare, clearly warning him to back off.
In her eyes, Ren was nothing more than a plant arranged by the black market.
Otherwise, why would someone suddenly bid on an item no one cared about moments ago?
Obviously, the black market was trying to artificially drive up the price.
Even Kuroichi on the stage cast Ren a grateful look.
While eight hundred million yen still fell short of her ideal target, it was at least something she could justify afterward.
Clearly, even she assumed Ren was bidding out of gratitude for how well his items had sold.
"One billion yen."
What neither Kuroichi nor the Kagamori heiress expected was that immediately after the 800 million yen bid, Ren would follow up without the slightest hesitation—
Adding another 200 million yen in one breath.
"Is this how your black market does business?" Kagamori Aoi snapped, finally losing her temper."Secretly planting people to keep inflating the price?"
As the Kagamori family's eldest daughter, she might be rich—but she wasn't stupid.
An item she could have bought for 500 million yen had now been forcibly doubled in price.
The Serum Inhibitor was nice, but it wasn't essential.
Compared to ordinary people, exorcists faced far lower risks when using yokai serum.
Their willpower and physiques were already far stronger, and their spiritual energy gave them greater resistance against yokai corruption.
Kagamori Aoi only wanted the Serum Inhibitor as an added layer of insurance.
Even without it, she was highly confident she could withstand the serum's effects.