Spiritual power (Reiryoku) and Demonic Energy (Yōki) were the two completely different supernatural forces of this age.
In the three months since Shinji had transmigrated, he was no longer the newbie… new corpse that had first woken up in that pile of bodies.
He had a basic understanding of this now.
Demonic energy originated from the world's impure vapors and the resentment of living beings. It was the very foundation of a yokai's existence.
This power was cold, decaying, carried an instinctive urge to destroy, and was laced with all kinds of worldly desires.
When it flowed through a yokai's body, it naturally eroded reason, amplified desires, turning the weak bloodthirsty and the strong insane.
Shinji himself was a living example.
Right after he became a demon warrior, his mind had been flooded with the urge to kill. He'd almost started gnawing on the corpses right there on the battlefield.
Luckily, he wasn't a truly newborn yokai. He was a transmigrator with complete human memories and cognition, thanks to the system. His willpower was strong enough to forcibly suppress that instinct and claw his way back to reason,
But the influence of that primal resentment still lingered. The biggest sign was that, as a corpse, he still experienced all kinds of desires and instinctual reactions driven by his demonic energy, just as many as when he was alive.
Though dead, he was like the living, which is what made him a yokai, both strange and monstrous. But he still wasn't truly alive.
Spiritual power was the complete opposite.
It came from the pure faith of humans, a guardian of order.
Spiritual power was clear, bright, carrying a quality that purified everything.
Humans who cultivated spiritual power were called exorcists, onmyōji, monks, shrine maidens – the names varied, but the essence was the same.
The purer one's faith, the stronger their spiritual power.
They were the natural enemies of yokai.
Spiritual power had an inherent restraining effect on yokai, like boiling water on ice, like blazing sun on haze.
Even a glancing touch from spiritual power would cause a yokai's body intense, searing pain, like a branding iron rolling across their skin.
That was why, when Shinji sensed that spiritual energy signature in the distance, his first reaction was wariness, not excitement.
"Here they come."
He stood on the hill, his red demon mask betraying no expression, only those crimson eyes fixed on the distant horizon.
That massive wave of demonic energy was now close enough to see with the naked eye.
A tide of grey-green miasma spread across the mountains and plains, surging and boiling, nearly staining the entire night sky a murky colour.
Within the miasma, countless black specks were densely packed, moving rapidly, emitting earth-shaking howls and screeches.
Those black specks were yokai.
Small yokai.
Trash even weaker than the five blue-skinned goblins from earlier.
Shinji squinted, trying to count how many there were.
One, two, three… ten… thirty… fifty…
"Damn."
He gave up counting.
Because it was impossible.
There were at least three or four hundred of them, packed so tightly together that from a distance they looked like a massive, writhing glob of grey-green mud.
This was the largest group of yokai he'd seen since transmigrating.
Even the great battle three months ago, the one that killed him on arrival, hadn't spawned this many yokai on the battlefield.
"The hell is this, a Night Parade of One Hundred Demons or something?"
Shinji stared at the sky-darkening swarm, his scalp tingling.
Sure, individually they were small fry, but too many ants could still kill an elephant.
He didn't think he had what it took to fight three hundred of them alone. If he got caught in that, he'd probably be drowned in the horde, have his demonic energy drained, and get torn to pieces.
But his attention quickly shifted away from the swarm itself.
Because he realized that the spiritual energy signature was right in the middle of it.
Shinji's gaze pierced through the layer upon layer of yokai shadows and landed on an incongruous figure at the core of the swarm.
It was a person.
An old man.
From this distance, even Shinji could only make out a blurry silhouette.
The old man wore a grey-white robe, his figure hunched. In his left hand, he seemed to be holding something; his right hand swung continuously, each motion unleashing a burst of light that blasted back the small yokai swarming around him.
Spiritual power constantly radiated from his body, glaringly bright against the night.
But that light was already very faint.
Growing fainter by the second.
Like a candle flickering in the wind, on the verge of going out at any moment.
Shinji could tell the old man's situation was dire.
His movements were slowing down, his spiritual power fluctuations weakening, and his injuries seemed to be piling up.
He fought as he retreated in a certain direction, but the yokai around him kept multiplying, threatening to swallow him whole.
"Hand it over!"
A sharp, jeering voice carried across the distance, borne by the night wind into Shinji's ears.
"Old bastard, hand that thing over!"
"Everyone who came out of your crappy village with you is already dead! What are you still holding out for?"
"Hand it over and we'll give you a quick death! Something like that isn't something you humans get to keep to yourselves!"
"We're in a good mood today, might even let you keep your corpse in one piece!"
Taunts, threats, and roars rose and fell in waves. Those yokai seemed dead set on getting whatever the old man was holding.
The old man didn't respond. He just gritted his teeth and kept moving forward.
He seemed to have a specific destination in mind.
Shinji followed the direction the old man was heading. That way led to the sprawling mountain ranges.
Further on, if his sense of direction wasn't wrong…
There should be a human settlement a few mountains over. A small province called Musashi, if he remembered right.
He was mulling this over when the Muramasa in his hand suddenly started trembling even more violently.
The whole blade emitted a low, humming vibration, like the hungry whimper of a beast deep in its throat.
Shinji looked down at the system panel.
[Cursed Blade Muramasa: Detected a large number of prey.]
[Current Mood: Ecstatic.]
[It conveys a strong desire to you: 'I want it'.]
"Calm down."
Shinji pressed down on the hilt, feeling like he was trying to soothe a rabid dog.
"That's three or four hundred, not three or four. If we just charge straight in like that, both of us are getting taken out there."
Muramasa ignored his advice and kept trembling violently.
[Cursed Blade Muramasa indicates it does not care.]
[It believes: Dying in a pile of prey is also a kind of romance.]
"…"
Shinji fell silent.
'Is there something wrong with this sword's brain?
And you're a sword, how the hell would you die? I'm the one who'd be dying here!'
He couldn't be bothered to argue with the blade anymore and turned his attention back to the distant battlefield.
The old man's situation was getting worse.
His spiritual power was almost completely spent. The barrier of light that pushed back the yokai was shrinking, growing dimmer.
The surrounding yokai noticed this too. Their attacks grew fiercer, their jeering louder.
"The old bastard's dying!"
"Charge! First come, first served!"
Shinji watched the scene unfold, lost in brief thought.
He was weighing something.
Step in, or not?
From a purely selfish standpoint, sure, the group of yokai was massive, but individually they were all small fry.
As long as he was careful, skimmed the surface and then got out, the risk wasn't that high, right?
And if he fed them to the blade… even if only a tenth of them…
He glanced down at the panel.
[Cursed Blade Muramasa: Current Affection 16]
[Next Stage (30) Unlocks: Bond Dialogue (2), Special Ability (1)]
Affection 30, and he'd unlock the first special ability.
That was exactly what he needed most right now.
Relying solely on the blade's increased sharpness wasn't enough to let him stand firm in this world overrun by monsters. Unlocking a special ability was the only way to truly create some distance between himself and your average yokai.
Three or four hundred small fry. Plenty to go around. Should be enough to push affection to 30.
As long as he was careful, didn't get surrounded, used movement to buy space, and space to buy time, nothing should go wrong and if it did, with his [Phantom Step], running wouldn't be a problem.
But setting aside personal gain, from a moral standpoint…
Well, he was a yokai. Morality wasn't really his thing. It was all about the gain, maybe with a tiny bit of leftover discomfort from his human days thrown in.
Plus, those yokai were shouting about some kind of treasure. That piqued his interest.
He'd been walking through battlefields for the three months since arriving in this world, picking up whatever half-decent stuff he could find here and there. But something that yokai would actually call a "treasure"? He hadn't come across anything like that.
His system was sorely lacking in so-called 'treasures.'
And those yokai were just too damn loud. Their screeching was getting on his nerves.
Well, no point in hesitating now.
Time to eat!
Shinji stood up and drew Muramasa from his waist.
The blade gleamed coldly in the moonlight.
"Gotta grind that affection anyway. Saving a guy on the side can't hurt."
Demonic energy surged beneath his feet, and his form vanished from the spot in an instant.
[Phantom Step].
The next moment, he was at the bottom of the hill, charging straight at the oncoming tide of yokai.
"Let's go!"