"Well then, I wonder what’s inside that armor of yours?"

The hero walks toward me slowly.

"...Huh?"

But midway, the hero suddenly drops to one knee.

"What the...? I... I can't breathe! It’s suffocating!"

Finally, it seems the effects have started to show. Even though I, the old man, was at my limit long ago.

"Hah... Hah... What did you do to me!?"

"Hah... No obligation to answer that."

Sorry, but I’m not the type of old man who would arrogantly reveal his secrets in the middle of a fight.

"Dammit, is this poison? Or paralysis!? High Cure! High Heal!"

The hero's body glows. It seems he can also use status recovery magic.

"Hah... Hah... Dammit, it’s not working! What the hell did you do!?"

Unfortunately for him, it’s neither poison nor paralysis.

Actually, even I am in a pretty precarious state at the moment...

Barrier.

A semi-transparent barrier appears before me. At the same time, I deactivate a portion of the barrier magic I’ve been maintaining all this time.

"Hah... Hah..."

Ah, fresh air tastes so good. But if I breathe too deeply now, I might end up hyperventilating. I need to calm my breathing.

You see, right before launching my attacks, I set up a wide-ranging barrier that enclosed both myself and the hero in a sealed space—without him realizing.

In this enclosed space, repeatedly casting fire magic has an inevitable consequence: oxygen depletion.

This world may operate on magic, but scientific principles still apply. I’ve tested it before.

Oxygen deficiency isn’t something status recovery magic can cure. Maybe it could heal the condition temporarily, but without oxygen in the environment, the problem returns instantly.

"Hah... Hah... Damn it, my head... It hurts..."

When oxygen levels drop, it becomes hard to breathe, dizziness sets in, and the head starts throbbing.

The original plan was to overwhelm the hero with the combined power of the Demon King's Four Heavenly Kings and our elite officers. But as a backup, I devised a plan to fight the hero on my own, just in case. When you reach my age, you always prepare for worst-case scenarios. And today, that caution paid off.

All that’s left is for the hero to succumb to oxygen deprivation.

"Hah... Hah... It's that barrier, isn’t it!?"

The hero glares at my visible barrier. His guess is, in a sense, correct. If he slashes through the barrier with his magic-nullifying holy sword, fresh air from outside would rush in, alleviating his condition.

But I didn’t come this far without additional precautions.

"Flame Burial!"

Summoning the last of my strength, I cast my most powerful fire spell once more. A massive fireball materializes before me.

"Take this!"

I unleash the fireball toward the hero, deactivating the front part of the barrier at the last moment to let the spell through.

"Wha—!?"

The fireball, fueled by the sudden influx of oxygen, erupts into an even greater blaze as it consumes the hero.

"AAARGH!!"

This is a backdraft.

In a sealed space, flames consume all available oxygen, filling the area with heated carbon monoxide. When fresh air is suddenly introduced, a rapid chemical reaction occurs, resulting in an explosive combustion.

The Flame Burial spell directly hit the oxygen-deprived hero, engulfing him in flames and obliterating the area.

"Even a hero can’t survive that. Rest in peace..."

The spot where the hero once stood is still burning intensely, but my skill to detect life signals confirms that his presence has vanished.

"So, this is what it feels like to kill someone... No, I’ll reflect on it later! First, I need to get Jilbe and the others back to the Demon King’s castle for treatment!"

I turn and begin heading toward Jilbe and the rest.

Recovering the hero’s body and the holy sword can wait. For now, the flames make retrieval impossible.

"What the hell!?"

"YOU’VE GOT TO BE KIDDING ME!!"

Just as I turn away, my life detection skill suddenly picks up a signal again.

Spinning around, I see the hero charging at me, his face twisted in a demonic rage. Before I can react, he tackles me to the ground.

"YOU DAMN BASTARD! I DIED ONCE, YOU KNOW!?"

I definitely confirmed the hero’s life force had vanished. Yet here he is, alive and furious.

"What... What’s going on?"

My confusion slips out as words.

"YOU PIECE OF TRASH! YOU WON’T GET OFF EASY NOW! No worries though—this is my Divine Domain! You have no chance of winning now!"

"Damn it!"

I realize I’m already within the glowing golden pillar of the hero’s Divine Domain.

"Serves you right, Demon King! This is my other cheat skill: One More Life! It lets me come back from the dead once! I wanted to save it as insurance, but thanks to you, I had to use it! Now, I’ll kill you slowly and painfully!"

What kind of ridiculous cheat skill is that!? As if his first cheat wasn’t enough, he has another one!?

"But this skill only works once! I wanted to save it for later, but whatever! Now, I’ll take my time killing you!"

Confident in his victory, the hero begins bragging about his powers.

Damn it, with his buffs and my debuffs in place, I stand no chance.

Though his golden armor and accessories were destroyed in the explosion, and he’s currently unarmed, I’m exhausted and unable to use magic for a while. It seems this is the end for me...

"How’s that, Demon King? Can’t move well, huh? That’s because my Divine Domain doubles the power of all humans within its range and halves the power of all demons! It’s a fourfold advantage for me! But hey, credit where it’s due—you lasted this long against me even with the odds stacked against you!"

...Wait. Humans get a buff, and demons are debuffed?

"Now then, let’s see what’s under that armor!"

As the hero reaches for my helmet, I grab his outstretched arm and twist it hard. His arm bends at an unnatural angle.

"GYAAAH!!"

It seems the hero's buff also applies to me, as I’m a human too.