["You."]

Mammon spoke while standing before half of the city, which had vanished as if evaporated.

["You made a wish contract."]

The lava he had poured out to annihilate the humans was no more. That, too, had already evaporated.

["You went and made a wish contract with a human."]

The same was true for his physical body, which had been reduced by half. Mammon covered his missing half with his hand, digging his nails in.

Even though the domain he ruled over was not Wrath, rage surged up within him.

["You...!"]

Contracts between humans and demons were usually rental contracts.

And a rental contract was a format where, once the contractor paid a price, the demon lent power equal to the price received.

Whether they used the received price to strengthen themselves or trade with other demons, they first had to lend their power to the contractor.

However, from a demon's perspective, a rental contract saved them the hassle of moving themselves, and even if the contractor died, they only lost the lent power—which they could even recover if lucky—so it wasn't much of a loss to the demon.

But what about a wish contract?

A wish contract was a bit different. The offered sacrifice was unconditionally given to the demon in the form of power, and in exchange for receiving it, the demon had to grant the contractor's wish.

Since they didn't lend their power, they wouldn't lose it even if the contractor died, but in return, they had to accept taking action themselves.

Furthermore, a wish contract had to be fulfilled even if the contractor died. If the wish had many loopholes, they could squirm their way out of it, but if there were no loopholes, it could become a contract full of nothing but losses for the demon.

This was especially true depending on the format of the wish.

["But with who on earth? I couldn't find any traces of a contract on you..."]

However, there was an advantage to such wish contracts. Exclusive to wish contracts, they could receive power straight from ancient magic every time a sacrifice was offered.

Not just the first time, but every single time a mutual agreement was reached between the contractor and the demon.

Just like how Mephisto had bypassed everything just now and received power straight from the supreme providence.

["Don't tell me?"]

["You're slow to catch on."]

But who had that bastard Mephisto contracted with, and what on earth did that contractor demand as their wish?

While deducing this, Mammon came to a profound realization.

["Right, I knew something was strange. Even though there's no way you would cling to a vessel in such a disadvantageous situation...!"]

Before the fight began, he had thought there must be a reason why Mephisto refused to give up the vessel, even at the risk of having his soul captured by Satan or himself.

For example... he wondered if the human's soul was trying to hold onto Mephisto's soul, making him unable to abandon the vessel.

But... what if the human's soul and Mephisto had made a wish contract? What if the human made it their wish that Mephisto would never abandon the vessel and flee under any circumstances?

If they ensured he couldn't escape the vessel at any moment, even at the cost of being consumed themselves...

["It seems your contractor wanted to go down together with you...?"]

If the vessel shattered while Mephisto was unable to escape it, Mephisto would die along with it. Recalling the nature of the vessel that hated demons, it might be a very possible scenario.

The problem now was that setting up such a hypothesis couldn't explain what had just happened.

Indeed, if the contractor truly wanted to perish together with Mephisto, what reason would there be for them to grant him power just now?

["Right. That's why it's quite a headache."]

["... My, since you're admitting it so obediently, it suddenly feels like it's not the case."]

["You have too little trust. It's sad."]

... No. There might be a reason.

Mammon remembered how Mephisto had pointlessly cleared the Hero out of the way earlier.

If Mephisto's contractor intended to protect humans, if they prioritized saving someone over perishing with the demon... then a contradiction like just now could be explained.

Mephisto had definitely formed a contract with the original owner of the vessel. The conditions of the contract were still uncertain, but clearly...

["When you keep hiding things like this... how am I supposed to believe you!"]

Mammon gathered his remaining demonic energy to firmly solidify his defenses.

How on earth did he hide the contract? He tossed the unresolved question aside. It wouldn't be too late to figure that out later.

BANG! BANG! What was urgent right now was keeping Mephisto in check as he rushed in, aiming at his regeneration.

["Damn it!"]

Unlike Mephistopheles, his regeneration was quite weak. There was a reason why he had laid out lava to hide his body and solely chipped away with long-range attacks without giving up distance.

However, that balance became precarious when half of his body was blown away. If he focused on defense, his body would collapse, and if he focused on recovery, Mephisto's attacks were too fierce.

Resentment welled up in Mammon over this. The situation caused by unexpected variables continuously piercing through the areas he had felt secure about was far too painful.

["What's wrong, didn't you say you'd enjoy watching my final struggles! Where did that guy go?! Huh?!"]

["Damn it!"]

The soaring lava was slashed. The sword strike that dug through it exploded at some point, shaking the defensive barrier he had wrapped around himself.

And the moment it seemed even a slight hole had opened, Ratel struck in, sharp as a needle. Just the task of pushing it back out set his every nerve on edge.

But what was even more infuriating was that in all these moments, the demonic energy Mephisto used was nothing but a minuscule amount. Having seized the upper hand, the bastard pushed him into a corner while only consuming the amount that naturally recovered.

Unlike himself, who was suffering extreme consumption while scrambling to defend.

If this kept up, he would lose. Mammon realized this.

["King! Do something!"]

He tried to urge Satan, who must at least be watching. However, he did not intervene. It was likely because the blessing he had already granted had taken enough of a toll on him. That was understandable.

["Damn it!"]

It was understandable, but resentment still lingered. He was on the verge of dying right now, so it was only natural.

["No, no, I said no!"]

'I don't want to die here. I don't want to die here. I, I must get my hands on everything in the world.'

["You, you! If you kill me, you'll be alone forever—!"]

["Now that you think you're gonna lose, you want to threaten me?"]

Mammon desperately attempted to make a deal. To Lee Shin, Mephisto was also an invader just like him. In such a situation, turning his back on Hell, which could be an ally, would be a loss for Mephisto as well—that was his point.

["But what to do?"]

But was there any way that would work?

["Because a world with only enemies is familiar to me."]

His opponent was Wrath, who had wanted to destroy even Hell.

CRUNCH!

Ratel pierced through all of Mammon's defenses and finally lodged into his body. Mephistopheles's physical body wasn't completely unharmed either, but he ignored his melting flesh entirely and only locked eyes with Mammon.

["It's about time we finish this."]

The horizontal pupils within the crimson light sneered at him.

Recalling the misfortune that had struck him like a disaster for no reason, all the hardships he suffered because of it, and all the humiliation he had to endure during his incredibly feeble days, Mephistopheles fully erupted with all that hatred.

.

.

.

SHK!

From within a crater tens of meters in diameter, Mephisto pulled out Ratel. The remaining corpse of Mammon was completely torn and shattered, mostly in the form of fragments.

Although his name and the power he possessed hadn't scattered just yet.

「... He's still alive.」

The one who had become exhausted from consuming a portion of their soul in the meantime whispered dryly. The voice demanding the fulfillment of the promise was truly firm even while cracked and dry.

'You want me to kill that too?'

「Your life will be in danger too if you come back leaving that alone.」

That wasn't wrong. Mephisto quickly agreed.

But to just follow along like that... hurt his pride a little.

'The corpse is mine.'

Since he didn't want to work without a price, he needed to take something. He said as much, and the contractor said nothing. It was a silent permission.

Knowing that with their soul reduced, the stronger Mephisto got, the more they would lose, yet also knowing that he wouldn't move without permission, they finally yielded.

The corners of Mephisto's mouth curled up in a sneer.

["O ancient magic."]

Of course, to do that, Mephisto also had to invest what needed to be invested.

He conjured flames to draw an impromptu magic circle, and offered up Mammon's name and power, which he was holding onto with demonic energy, in the position of a sacrifice.

Since it would either be purified by the priests or snatched by other demons if left alone anyway, he had no hesitation in offering it as a sacrifice.

["O supreme law."]

WHOOSH, WHOOSH. The flames that bloomed from all directions danced and chanted the spell in his stead. Every time the multiple mouths of flames carved the magic, the thick, heavy night grew even blacker.

["O scales of the universe."]

And at the time when the world was at its darkest. The scales tipped.

["A proper price."]

Mephistopheles's sword moved once again.

──! Heat that devoured even sound deleted the coastal area of the city. The only thing left there was the shell of the turtle, upon which he had intentionally applied weaker force.

Of course, only the form remained; the insides would have been completely cooked. Being primeval beasts as they claimed to be, only the snake that had hidden inside it would be barely hanging onto its life.

["Hmm. Was there no need to offer the name as well? There's too much of a surplus."]

If this was going to happen, maybe he should have wished to increase his total amount of power instead of a temporary buff format. He had chosen the former because the latter didn't grant power immediately.

Even so, he didn't have the time to eat and digest it himself, and it wasn't worth it since it would only muddy his essence. The contractor wouldn't just sit and watch him do that in the first place anyway.

In the end, this had been the best option.

While feeling regretful over the power that would evaporate once this time ended, Mephisto steadily launched a second strike. The flying flames burned away the turtle's shell as if gnawing at it, leaving only the white snake behind completely exposed.

["Eat."]

What came next was already decided. Ratel, thrown forward, received the highly inflated power and bulked up its size.

CHOMP!

A giant badger bit into the snake's neck and swallowed it whole.

Of course, it wasn't really eating to digest it. Ratel was not a living creature, but merely an intricate device.

Instead, the inside of Ratel's body—a rift connected to the outside of the world—was forcibly opened, cramming that massive thing inside. This, too, would have been impossible without the buff.

Taking it out later might be a bit of a problem, but by then, the useless body would have all melted away and only the core would remain compressed, so it wouldn't matter.

Mephisto flicked his finger, satisfied with what he had obtained.

「... Come back now.」

Suddenly, the contractor who had been watching all of this weakly brought up the final condition.

'So impatient. Considering how I got this opportunity, just a little bit is fine, isn't it.'

But was there any reason for him to listen? Mephisto sneered and put strength into his feet.

THUD. With a light step, his body momentarily vanished. No. His instantaneously moved body stepped outside the crater.

The coat draped over his shoulders fluttered like a cape.

「The promise...」

'Unconditionally save a specific individual. Once survival is secured, return control to Gretchen. Additionally, do not lay a single finger on the humans, and protect them if possible. Things like that.'

Having to return control was annoying, but it was better than dying a dog's death at Mammon's hands without even being able to put up a fight. That was also why he accepted it.

'But look, is survival really secured?'

But was there any reason to return control immediately? Let alone after fighting on the side of humans—regardless of his inner thoughts, he did protect them, didn't he?—right after he had gone on a proper rampage as a demon?

Mephisto knew. The fear that overwhelmingly strong power brought.

In such a situation, even if Gretchen took control again, would the humans try to keep this physical body alive? Wouldn't they rather feel it was safer to kill him when Gretchen held control, meaning when he was weakened?

'Ancient magic is tolerating this too. The safety of this body isn't secured yet.'

What was the reason he killed Mammon, even going so far as to turn Hell into an enemy—strictly speaking, he had never considered Hell an ally, so saying he 'turned it into an enemy' was a bit off—but still? It was for survival.

But for the body he had saved like that to die a vain death at the hands of humans? Now that would truly be an unfunny turn of events.

Mephistopheles didn't want to leave such a risk behind. He needed a more certain guarantee.

A more undeniable assurance.

「You bastard...」

'Don't worry. I'm not going to kill them.'

With his personality, he would have prevented any potential danger by massacring everything... but the contract itself blocked that. So he had no choice but to use another method.

A deceptive move that would entirely block even the possibility of Gretchen stepping forward and asking them to kill him when Gretchen returns.

He approached the humans step by step. He could feel his pitiful contractor stiffening up with tension, but that only made him more amused.

Because his own misfortune was only obscured when others were miserable.

"... He—he's coming."

Fortunately, the humans didn't blindly point their weapons at him. The stupid lackeys of the Two Gods were the same.

Now that all the demons had fled to avoid Mephistopheles, securing immediate safety and a bit of breathing room, they didn't rush in just because he was a demon, even if their faces were stiff. They merely looked at him with wary, terrified eyes.

And that was exactly what pleased Mephisto quite a bit. Indeed, it was only when he reigned with terror that the world Mephisto knew became somewhat peaceful.

["Who's the leader?"]

If he had it his way, he would want to maintain this exact state... but there was no way a pushover like Gretchen would let him.

Damn Gretchen. Truly never making the situation easy.

"Lord!"

Not long after, someone stepped forward, braving the objections of countless people.

It was someone he remembered seeing through Gretchen's vision. Perhaps the master of this city (or what used to be it)?

He had expected the Hero to come out, so this was unexpected. Or maybe not. Sensing their presence, it seemed they were still unconscious.

"... Who are you?"

["Are you asking because you don't know? I feel like those servants of the Two Gods would have already said everything."]

Anyway, what mattered was compromise. Mephistopheles chuckled and changed Ratel's form. Ratel, which had turned into a chair, supported his body while mocking the agitated soldiers.

["I am Wrath, one of the Great Demons you bastards so desperately want to kill."]

"..."

["At the same time, I am also a being who has no need to listen to Satan's orders."]

"... Does that explain what just happened?"

["Explain? No, no."]

Mephistopheles slowly crossed his legs. The composure flowing from his crossed legs became a form of pressure when it reached the humans.

["This is a notification."]

The red eyes between the goat bones smiled broadly.

["You see, I don't want to lose this vessel I barely obtained."]

"... Whatever do you mean by that."

["For instance, something like this."]

Simultaneously, a cracking sound rang out, and the bone fractured. The white hair that had been haphazardly hanging down so long it dragged on the floor began to shrink up and up, taking on the color of the night. It was hair where ash and night coexisted.

CRUNCH. At the same time, his body, covered in black demonic energy and Ratel, grew even thicker, and the form of his clothes changed into a familiar one.

"... Boss!"

"Demon Knight...!"

["A notification of the fact that the moment you try to plunge a blade into this guy's heart, I will pop out."]

The moment the pitch-black demonic energy swept over his face last. The moment the bone mask completely crumbled with a cracking sound.

With his face fully revealed, Mephistopheles smiled. It was a smile formed on the face of the Demon Knight.