The Hero’s Mentor is a Demon (King) Witch

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In the past.

As I deployed the monsters to the frontline, I found myself deep in thought.

‘Isn’t it better for the enemy if the monsters die?’

Every monster has a magic stone in its heart.

Every being that uses mana possesses a magic stone in its heart.

Even slimes, when they accumulate a certain amount of mana, have a substance that, while it may not quite be called a ‘magic stone’, is an embodiment of dark mana.

We refer to this substance as ‘magic core’.

There is a great variety of these magic cores.

For instance, in the case of a lich, one might base their magical power on a specific object like a ‘life vessel’.

Living armor has the magic circle engraved on the armor itself which serves as the magic core.

There are even martial artists from the east who create a ‘danjeon’ in their lower abdomen, causing mana itself to concentrate and function like a magic core.

In cases such as the dragon’s ‘dragon heart’, an actual organ of the body fulfills the role of a magic core.

Entities like me, classified as ‘fleshly spirits’, create a magic core that embeds my consciousness into the heart of whatever object I inhabit.

And most monsters possess a magic stone in their heart.

Unlike human mages who form circles around their hearts to use mana, monsters cover their bodies with mana mixed with their blood.

Naturally, this leads to the formation of stones like bladder stones in the heart, which are often referred to as a monster’s ‘magic stone’.

However, the amount of mana contained in this magic stone is nearly seventy percent of the overall mana present in the monster’s body.

Even if one uses a lot of mana, as long as it’s not to the point of depletion for a long time, most of that mana remains in the magic stone.

Mana flows through blood vessels, invigorating the entire body, so most monsters die while still retaining their own mana because they can’t actively manipulate it.

‘During my time living with the Hero Party, I realized that just throwing monsters to their doom benefits the enemy.’

Weak monsters only provide advantages to the enemy.

Even if a single goblin were to trade one-for-one with an ordinary civilian, what does it mean when a mage seizes the magic stone from that goblin and blows up dozens of goblins in their village?

And using a monster as powerful as a dragon?

Then humans would gladly gather in droves to hunt it down.

Having witnessed such scenes repeatedly while infiltrating various Hero Parties, I understood better than anyone how humans effectively utilized the magic stones in monsters’ hearts.

So the answer was ‘poison bugs’.

There’s nothing quite as effective for pure lethality without providing any benefit to the enemy as tiny, venomous creatures.

I had truly enjoyed myself properly.

And now I was on the receiving end of this…

“This is infuriating.”

Mana depletes in real time, yet I gain none from eliminating the enemy.

No matter how much mana I secured from the Normans, maintaining a barrier that covers the entire village is virtually impossible.

“Master, are you okay?”

“Thanks for your concern. But if this keeps up…”

Flare!

The flame-infused Nepenthes trapped yet more poison bugs.

Not a single one passed through the catching net, and the barrier was almost perfect with not even a slight opening.

However.

“…It might break in less than three hours.”

“What? What do you mean?”

“That barrier is a deployed magic. It’s different from the one in the city. If I were a resident here, I would have set up a semi-permanent barrier, but since this one was set up in just a day, it will weaken over time.”

It’s only natural.

“Let’s say it takes 1 mana to catch a single poison bug. It cost 8,000 mana to set up the barrier. But how many poison bugs are there?”

Only the visible ones number in the thousands, no, tens of thousands.

“They’re chipping away at the mana embedded in the barrier with sheer physical assault. They’re literally burning themselves to break it down. In real time.”

“T-then what should we do?”

“Thankfully, if I inject mana into the barrier, I can extend the time, but…”

Oh? Look at this.

‘Humans will always be humans.’

As soon as I suggested that it might be okay, I could see everyone relaxing and letting their guard down.

“Maintaining the barrier requires a constant supply of mana, you know? I’m not like a dragon to have infinite mana, so the longer it goes on, the more my mana will deplete.”

“That absolutely cannot happen!”

Lucius suddenly shouted loudly.

His voice was so booming that even I was shocked by it.

“If you deplete all your mana, you won’t be able to deal with those poison bugs.”

“But if we could just…”

“Is there no other way, Master?”

“There is.”

Thanks to Lucius, it became easier to set up a build-up.

As expected, Lucius is a good, useful warrior.

“First, if there’s a magic stone in the house of the deceased mage, please bring that. Even that might allow us to extend the barrier for an extra minute. Does anyone have a magic stone?”

“…”

There was no answer.

It was as if everyone had sewn their mouths shut, refusing to speak.

‘Of course, humans would be like this.’

I could feel it.

The magic stones scattered throughout this village.

Because magic stones can be liquidated like gold or gems, most humans possess plenty of them at home.

I didn’t bring up the magic stones for no reason.

If I could gather all the magic stones from the village, I could surely extract at least a day’s worth of mana.

“…….Does no one have a magic stone? Slime or goblin magic stones are fine too.”

There was no response.

Now, they were simply glancing at each other without even minding me.

‘This is why humans are troublesome.’

Even in a life-threatening situation, as soon as there’s a glimmer of hope, they reveal their selfishness.

And yet…

“Um, um… We have some magic stones at our house! Can I go get them now?”

There are also altruistic ones like this.

I turned to the boy who still bore none of humanity’s dirty desires, offering him a benevolent smile as I patted him on the shoulder.

“Please do. I will repay you later.”

This boy’s family.

The house with the least amount of magic stones.

Yet here he is, the first to voluntarily offer to bring me some, shining like a ray of light in pitch darkness—how could I possibly despise him?

“I’ll be right back!”

“M-Master! I’ll check if we have some too!”

“Please go. I’ve set up barriers all the way to the village fence, so inside the fence at least should be safe.”

As the boy left his seat, others began to depart one by one to check their own homes for magic stones.

Some will genuinely bring them back, while others will pretend to check so as not to draw attention to themselves, and some will hide their magic stones in the ground and pretend to rediscover them later.

‘This is why humans are interesting.’

Even in times of danger, they display such a variety of personalities—it’s truly a fascinating and lovable race.

Hope and despair coexist simultaneously, a mix of heroes, villains, and petty individuals woven together in such an attractive way.

Thus, instead of annihilating them, I chose the path of domination.

“…….”

It may seem utterly insane to attempt to dominate beings as chaotic as these, but reflecting on it now, I feel glad I didn’t choose to eradicate humanity back then.

‘I’m glad I didn’t self-destruct.’

In the final moments.

“Witch, over here!”

“…So much?”

“Yes! You’re saving us, right? This is all we have, but… please use this!”

“Thank you. I appreciate your kindness. May the blessings of the Goddess and Mana be with you, and I will surely protect you.”

“Please, Witch!”

Despite my intent to destroy everything and obliterate the Intermediate Realm, perhaps it’s because there are humans like this that I ultimately did not go down that path.

If only there were nothing but trashy villains, maybe it would be different, but since there are these precious gems pulled from the muck, I can’t bring myself to annihilate humanity.

“Please gather the magic stones in the center of the plaza. I’ll check the deceased mage’s house for a bit.”

One by one, the magic stones began to accumulate, and I signaled to my party to gather at the house of the dead mage.

“Lucius. Rosmas. Sir Rapid. Lord Black Lotus.”

Currently, we have five people, including myself, capable of fighting.

“Sir Rapid, may I take the lead in this discussion? Dealing with the Demon Race is my specialty.”

“Ah, yes. Please.”

A declaration of expertise.

This essentially means that if I go wrong, I’ll take responsibility.

But if I wear the armband, I can certainly push away any unnecessary distractions.

Mostly the uncomfortable relationship between Black Lotus and Lucius.

“First, we need to consider this.”

I held up the magic circle connected to the center of Odrone, Ligret.

“As you can see, the magic circle is broken, right? Now that we’re not able to maintain consistent communication, the Adventurer Guild might notice the anomaly and come here.”

I don’t know the exact details behind the broken magic circle.

But what’s critical are the two choices that lay before us.

“Do we wait for reinforcements from Ligret? Or do we venture outside the barrier to eliminate the one controlling the poison bugs?”

“Master, which option conserves your mana better? Personally, I think eliminating the controller would be more effective.”

Lucius idly fiddled with his ring.

To those looking on, it may seem like a habit, but in reality, it was a pre-arranged gesture appealing to me.

“Let me think for a moment. I need to come up with a perfect plan.”

Hold out? Special ops? Gather people for a showdown? Sacrifice humans for infinite survival? Move everyone along with the barrier?

“What’s the most effective method…”

And then.

An always elaborate plan becomes nothing but bubbles due to the element of ‘Hero’.

“Witch, outside!!”

“……Oh no.”

A massive torrent of water blanketing the sky.

An overwhelming power trapping all the poison bugs in a watery vortex.

“That’s… the Power of the Holy Sword?”

The woman with flowing blue hair wielding the immense torrent at will.

The master of that holy sword—

“……Liriez Cesarcross?”

No way.

She could conceal the holy sword so perfectly that even I didn’t catch on.

“…….”

The moment I thought our eyes met.

She looked at me, blushing as she smiled widely.