After a while, Shion and Luna stood up, their expressions looking thoroughly satisfied.
"Haa... That was the best..."
"Yes... I could see that becoming a habit..."
At their feet—or rather, still hovering in mid-air—Sakuramochi was slumped over, panting heavily with a look of utter exhaustion.
"Why did I have to go through that...?"
Oliver shrugged his shoulders with a wry smile.
"...You've had a rough time, haven't you?"
"To think the day would come... when I’d be pitied by a human..." Sakuramochi muttered in a faint voice, his eyes staring off into the distance.
As the atmosphere settled down, I decided to ask again.
"...So, what exactly is this thing?"
Fuuka answered without a moment's hesitation.
"A manifestation of the consciousness that dwelt within Hakuyou. He started appearing after we established our cooperative relationship. In essence, he is an existence made of Yoryoku itself. That’s why he can answer the question you asked earlier, Orun."
"I see..." I nodded seriously, shifting my gaze back to Sakuramochi. "Then I'll ask you directly. What is Yoryoku?"
"Hah? Why the hell should I tell you?" The fox immediately turned his head away, his voice dripping with sulkiness.
In that instant, Fuuka’s eyes narrowed slightly.
"Sakuramochi. Don't be difficult."
Her voice was soft, yet it carried an undeniable pressure that seeped into the air. The fox's shoulders jerked. After a tense silence, he let out a heavy sigh.
"Tch... Fine, I get it. I just have to explain it, right? ...Good grief, to think I've fallen so low as to give a lecture to a human."
Sakuramochi snorted in dissatisfaction and adjusted his posture in the air. He gently swayed his ears and tail, and when he spoke again, his voice held an intellectual weight that was hard to reconcile with his pathetic state from moments ago.
"So, it was about Yoryoku, was it?"
"Yeah. I’m listening."
Sakuramochi exhaled once more before beginning his explanation.
"First off, Yoryoku is a power born from the 'negative emotions' dwelling within living beings. Anger, hatred, jealousy, fear. Those dark emotions are far more intense than Ki, which feeds on 'positive emotions.' Like fire consuming kindling, it swells until it transforms the individual into a monster."
The fox moved as if swimming through the air, fixing me with a sharp gaze.
"And humans abandoned it. The reason is simple: it was far too strong. There was no end to those who couldn't control it and ended up destroying themselves or their comrades. Over thousands of years, a mechanism to suppress Yoryoku was etched into the very genetic code of humanity. ...In other words, humans discarded Yoryoku as a 'power they couldn't handle.'"
There was a distinct edge of irony in his voice.
"However, only humans abandoned it. Other living creatures still possess it. On rare occasions, one of them is consumed by that power and becomes a beast. Humans call them 'Youkai,' and for generations, specific lineages like the Shinonome House have been tasked with exorcising them."
"Youkai... I’ve seen the name in old documents, but I’ve never actually encountered one. Are they really that rare?"
"They’re rare, certainly, but that’s not why you haven’t seen one."
"A different reason?"
"This world itself is designed to prevent Youkai from being born. It’s as simple as that."
"The world... You mean the Yoryoku of other animals is being suppressed by the Principles of Magic?"
"That’s the long and short of it. ...But I’ve digressed. Basically, Yoryoku is the polar opposite of Ki, but their roots are the same. They are both 'power flowing within the self.'"
I furrowed my brows at his words. "In that case, ancient humans could handle both Ki and Yoryoku. But because they spent so long discarding Yoryoku, they eventually lost the ability to manipulate Ki as well?"
"You're quick on the uptake," the fox stated matter-of-factly, swaying his pale cherry-blossom-colored tail. "Sealing away Yoryoku caused the circulation of Ki to become sluggish. That's why humans forgot the art of manipulating their 'inner power' and became small-minded, clever creatures that rely solely on their wits."
"...But the records say that during the Fairy Tale Era, people capable of using Ki began to appear again. How did that happen?"
At my question, the fox narrowed his eyes while drifting through the air.
"Likely because a new power called 'mana' emerged. It wasn't something innate to humans, but an energy that filled the environment. That provided the necessary stimulus."
"A stimulus...?"
"Yeah. As mana filled the world, the Ki sleeping inside humans began to stir in response. Mana and Ki are in a state of Mutual Antagonism, after all. Yang and Yin—when one grows stronger, the other inevitably wakes up."
I rested my chin in my hand, slowly processing his words. "...If Ki and mana share a relationship of Mutual Antagonism, then Yoryoku—the polar opposite of Ki—must share a relationship of Mutual Generation with mana, right?"
"Excellent deduction. Theoretically, that’s exactly right." Sakuramochi curled the corner of his mouth into a cynical smirk. "Though it’s still a power far beyond the reach of humans."
As I reached the essence of Yoryoku, I felt a click deep within my mind.
My ultimate technique—Final Form: Mont Ende.
Its core principle involves simultaneously refining both Ki and mana to their absolute limits and intentionally triggering Mutual Antagonism. While this pushes my physical abilities to the brink, it also generates the power to annihilate all creation through that very conflict.
However, doing so is equivalent to exercising the culmination of Ki—Evil-Bane. Since Evil-Bane is a power that erases mana, it carries the inherent risk of destroying my own body, which has become accustomed to the mana of my special ability.
But if—if I can place Yoryoku between the two...
The recoil generated by the antagonism could be softened by using Yoryoku as a 'buffer.' Instead of the Ki and mana within me consuming each other, they could maintain an equilibrium through the medium of Yoryoku.
If that were possible... I could establish a version of Final Form: Mont Ende that doesn't tear my own body apart.
I exhaled quietly. "...So Yoryoku really was the final piece."
At my murmur, Sakuramochi flicked his ears. "Hey, surely you aren't thinking you can handle Yoryoku yourself? I literally just told you. Humans can't use it. It’s written into your genes."
The fox's voice was cold, but his tail was swaying restlessly.
"You say that, but Fuuka can handle it, can't she? If so, there has to be a way."
When I countered his point, Sakuramochi fell silent for a moment. His ears stood straight up as he cast a sharp look toward Fuuka.
"I hate to admit it, but this brat is—"
"—Fuuka."
Fuuka, who had been listening quietly, corrected his choice of words.
"............ Fuuka is special," Sakuramochi corrected himself reluctantly. "She is of the Shinonome direct line—a clan that has spent centuries purging Youkai. On top of that, she is compatible with me, Hakuyou, the only Yoryoku permitted to exist in this world. It took all of those conditions being met for Fuuka to finally handle Yoryoku."
The fox stated this flatly before pulling his lips into a grin. "Well, even for her, she was so terrified of being consumed by it that she only used a measly, pathetic amount until very recently."
He swayed his tail mockingly, his eyes narrowing.
"You don't need to say that part," Fuuka interjected, looking annoyed.
"...So, the primary obstacle is the genetic suppression within us humans. Is that right?"
"...? Yeah, that's what I said." Sakuramochi snorted, swaying his tail as if I were stating the obvious.
"I’ve already got a lead on how to handle that through another matter, so it shouldn't be a problem. In fact, it might even be convenient. The real issue is how to learn the actual sensation of manipulating Yoryoku. Sakuramochi, do you know of any way I can grasp that sensation?"
"Even you're calling me by that fluffy name—wait, wait, wait! Why are you already assuming you'll be able to manipulate it?! This isn't something a single person can just 'figure out,' you know?"
As Sakuramochi grew flustered, Fuuka gave a small shrug.
"Sakuramochi, just as I am special, Orun is special in his own way. He has a special ability called All Creation. It allows him to handle powers he has seen or heard of."
"Hah? What kind of nonsense is that?" Sakuramochi looked at her with blatant exasperation.
"It's not quite so simple that I can master it just by seeing it once," I clarified. "That said, I’m planning to try a method different from All Creation this time."
"...You are?" Fuuka asked.
"Yeah. Well, I'll explain that later. I’m not entirely certain it’ll work yet. Anyway, back to the topic—do you know of any other methods?"
"...The fastest way would be to bond with me, Hakuyou. But that’s out of the question. I don't care how ridiculous your ability is; bonding requires the right bloodline."
I reflexively frowned at his words.
Bloodline... A principle similar to the inheritance of special abilities. Maybe an expanded interpretation of my ability...? No, that’s a stretch. Besides, Hakuyou is Fuuka's sword. I have no intention of taking it. If that’s the case—
"—Wait, there was one more thing," Sakuramochi spoke up, as if a memory had just surfaced.
"One more? You mean there's another cursed katana?"
"Yeah. Well, it's a cheap imitation that's insulting to even compare to me, but there's no doubt it contained Yoryoku."
"Where did you see this?"
"The sword carried by the man Fuuka exorcised."
Fuuka blinked repeatedly at his casual remark. "The one... I exorcised?"
"Oh, come on. He was right there. That boorish man you cut down at the bottom of the great pit this guy, Orun, opened up."
"............?"
Fuuka still looked confused, her head tilted to the side.
However, if he mentioned me being there, it had to be an enemy Fuuka and I fought together. We haven't had many joint battles. And as for a "great pit"...
"—The War Ogre?"
Zimon Ogre, one of the executives of the Cyclamen Cult. I had left him to Fuuka while I moved to engage "Rasetsu" Stieg. Zimon's weapon had been a greatsword, if I recalled correctly. Did that blade house Yoryoku?
"...Come to think of it, he was using a copper-colored sword. If that’s the one, I still have it. I collected it after I defeated him."
Fuuka reached into her Storage Magic Tool and pulled out the massive sword Zimon Ogre had wielded. "I'll give it to Orun."
I took the offered weapon with both hands. It was significantly heavier than I had anticipated.
"...Thank you, Fuuka. Thanks to this, the path I need to take is finally clear."
First priority: help Luna become a Transcendent and fulfill my promise to Titania. And then, master the use of Yoryoku.
I will achieve both. No matter what.
I gripped the hilt, feeling the solid weight in my palms, and quietly renewed my vow.