The moment the blue crystal—so different from the purple demonic power crystals—entered his mouth, the effect was immediate.
Almost instantaneous.
Ren Kuroda could clearly feel the spirit power within his body surging wildly, strengthening at an astonishing speed.
Before this, his spirit power had been stuck at roughly C-minus. But after swallowing this low-grade spirit power crystal, it skyrocketed—blasting straight into C-rank in the blink of an eye.
The exchange price of low-grade spirit power crystals was identical to that of demonic power crystals: one hundred reputation points per crystal in the exchange shop.
Although Ren had technically "paid" five hundred reputation points to draw it—on paper an obvious loss—he didn't feel even a trace of disappointment.
On the contrary, he felt like he'd made a killing.
Because whether it was a spirit power crystal or a demonic power crystal, once he had drawn it once, the system would permanently unlock it in the exchange shop.
Rather than pulling a single crystal, it was more accurate to say he had obtained permanent purchasing rights.
With his demonic power already at A-minus, achieving another breakthrough in the short term was nearly impossible.
But that didn't mean he couldn't continue getting stronger.
If demonic power couldn't be raised, then he'd just raise his spirit power instead.
His spirit power had only just reached C-rank—using low-grade spirit power crystals, rapid growth in a short time wasn't difficult at all.
In fact, Ren felt a twinge of regret.
If he'd known earlier that he would draw something like a low-grade spirit power crystal, he would have used all his remaining reputation to exchange crystals and boost his spirit power.
Unfortunately, he had already exchanged his reputation into coins.
And the system had made it very clear—no refunds.
Ren tossed the 1,000-reputation silver coin into the machine.
The massive device hummed to life again, lights flashing brilliantly.
Because this time the coin's value was higher, the reward grid refreshed entirely—another forty dazzling prizes replacing the previous ones.
At the 500-reputation tier, there were eight guaranteed skill slots.
At the 1,000-reputation tier, there were sixteen.
Double the guarantee.
Out of forty total slots, sixteen were skills—nearly two-fifths, almost a fifty percent chance.
That was ridiculously high.
With a sharp clang as the coin hit bottom, the light-train raced forward again, streaking past skill icons one after another.
Ren's heart clenched as the lights slowed.
Finally, they stopped on a grid marked with dark clouds and crackling lightning.
Judging by the position alone, it was unquestionably a skill reward.
And at first glance, Ren thought it was some kind of lightning-based spell.
After all, in onmyō techniques, lightning arts weren't rare—but among the five elemental spells, their destructive power was second to none.
However, when Ren read the system notification, he realized he'd been completely wrong.
Strangely enough, he didn't feel disappointed at all.
If anything, he felt ecstatic.
He even thought his luck today was bordering on absurd.
"Ding! Congratulations. You have obtained Wind, Forest, Fire, Mountain — Advanced Version."
Skill Name: Wind, Forest, Fire, Mountain (Advanced)Skill Rank: S+Skill Description: As the name implies, an advanced version of Wind, Forest, Fire, Mountain. This skill contains more powerful techniques as well as its ultimate secret art.
Learning Requirements:
Must possess the skill Wind, Forest, Fire, Mountain and have fully mastered it. (Completed)
Human Reputation level must reach "Well-Known Exorcist" or higher. (Completed)
A solid foundation is essential. Must possess a Grandmaster-level basic skill: Grandmaster Swordsmanship or Grandmaster Blade Arts. (Not Completed)
P.S.:Swift as the wind.Steady as the forest.Fierce as fire.Immovable as the mountain.Unfathomable as shadow.Striking as thunder.This battle shall be victorious.
Staring at the long wall of text, Ren froze completely.
This was the second S-rank skill he had ever obtained.
And it was an S+ at that.
Just like the previous S-rank skill he'd acquired, this one also required prerequisites to learn—
But compared to Demon King's Contract, the hurdles were far more brutal.
Ren had possessed Wind, Forest, Fire, Mountain for quite some time now. He had long since mastered its techniques, wielding them as naturally as his own limbs—and had even created a few variations of his own.
So the first requirement posed no problem.
As for the second—if this had been before his return to this world, he wouldn't have met it.
But now?
Thanks to everything he'd done recently, his Human Reputation had long surpassed his Yokai Reputation. He had already reached the level of "Famous Exorcist."
Requirement two was a non-issue.
The real problem was the third.
Whether swordsmanship or blade arts, both emphasized gradual progression.
Sometimes, with a sudden insight, one's realm could leap forward—just like Yamato Kuka's breakthrough during her battle against the Noppera-bō.
Ren's own foundational blade arts had already reached Advanced Blade Arts.
He was only one step away from Grandmaster Blade Arts.
But that single step…
He had no idea when he'd be able to cross it.
For low-level skills, perhaps one could simply grind—swinging a blade over and over to raise proficiency, advancing from beginner to intermediate.
But the leap from Advanced to Grandmaster required something far more elusive.
Even swinging ten thousand times a day—one hundred thousand times—without the right realization, a breakthrough would never come.
During his battle with Inugami Gyōbu Tanuki, Ren had felt the barrier of Advanced Blade Arts loosen slightly.
But it still wasn't enough.
Now, staring at the advanced version of Wind, Forest, Fire, Mountain, Ren felt his mouth water.
Yet he couldn't learn it.
An S+ skill—there was no way he wouldn't be tempted.
Once mastered, his combat power would skyrocket yet again.
Unlike Demon King's Contract, which leaned more toward support, Wind, Forest, Fire, Mountain (Advanced) was a pure offensive skill.
Just as Ren had long suspected, the version he originally obtained was incomplete.
Techniques based on the Big Dipper and the Seven Human Senses could never consist of only four forms.
This so-called "advanced version" perfectly answered the doubts he'd had before.
The remaining three forms—Unfathomable as Shadow, Striking as Thunder, and the ultimate secret art—likely corresponded to consciousness, sensory perception, and ālaya consciousness—the so-called microcosm.
Just how powerful this advanced version was, Ren couldn't say for sure.
But comparing the original's A+ rating to the advanced version's S+, the difference was easy enough to imagine.
Obtaining such a powerful skill—one perfectly suited to him—naturally made Ren happy.
But being forced to stare at it helplessly, unable to learn it, left him with an indescribably complicated mood.
It was like a stunning beauty, clothes half undone, enthusiastically inviting you to play a "little game"—
And you couldn't get it up.
With no choice, Ren tossed the advanced skill into a corner of his system space.
Right now, he was wrestling with another decision.
Because he'd drawn low-grade spirit power crystals, he was reconsidering his original plan.
Should he convert all of his remaining reputation into spirit power crystals and raise his spirit power as much as possible?
His spirit power was only C-rank.
Low-grade spirit power crystals were absurdly effective for him—the boost was massive and unmistakable.
With his remaining reputation, reaching A-minus might be unrealistic…
But B-rank was absolutely within reach.
At this point, Ren was like a hybrid vehicle—running on both demonic power and spirit power.
Other yokai or humans relied on one or the other.
But Ren had both.
Once his demonic power ran dry, he could simply switch to spirit power.
Of course, right now, his spirit power was nowhere near his demonic power.
And if he activated Half-Demonization, his spirit power wouldn't even come close.
But being unable to match didn't mean he couldn't close the gap.
He had originally planned to keep reputation in reserve to exchange for demonic power crystals—emergency fuel during battles.
But if his spirit power grew strong enough, it would be like gaining a second energy reserve.
Compared to gulping down demonic power crystals mid-fight, this option seemed even better.
And with another world-crossing likely happening tonight, facing an unknown world meant one thing—
The stronger he could get, the better.
After agonizing over it, Ren finally made his decision.
He exchanged his remaining eight hundred reputation points entirely for spirit power crystals—
And swallowed them all.
If an ordinary person experienced such a sudden surge of spirit power, their body would likely be damaged by the violent influx.
But Ren's demonic power had long since reached A-minus. His body was already accustomed to handling energy at that level.
As long as the explosive growth of spirit power didn't exceed his demonic power in Half-Demon form, his body could easily withstand it.
Eight blue crystals went down in succession.
Ren's freshly stabilized C-rank spirit power surged once more.
The density became so extreme that visible, tangible spirit power began radiating from his body.
His spirit power climbed relentlessly, smashing through layer after layer of barriers—
C-rank.C-plus.B-minus…
The storm of spirit power finally subsided.
When it ended, Ren Kuroda's spirit power had stabilized—
At B-minus rank.