Yandere Instruction Manual: My Wife is World Ending Calamity!

As Seles fell through the air after being thrown by Zenith mid-sentence, she didn’t even know how to react.

Didn’t he say I could rely on him?

Didn’t he say he would save me?

Then how could he simply throw me away like this?

And more importantly, why the hell is he himself jumping into the mouth of that monster?

Countless questions echoed through her mind.

She couldn’t understand how he knew things she had never told anyone. She couldn’t understand how he could claim that he was trying to save her.

And she couldn’t understand why he needed her specifically to rely on him when she was certain that her overly optimistic brother could have fulfilled the condition far more easily than she could.

Everything about Zenith screamed suspicious to her.

And yet, when he had said those words so sincerely right as she was about to be swallowed by that monster, she couldn’t help but rely on him.

She didn’t trust him.

But somehow she trusted him to save her as if he could defeat a monster which even her brother couldn’t do anything against.

Still, she wasn’t about to leave him alone if she survived this hell somehow, especially after all the secrets about her that he had revealed so casually.

Not to mention how he had claimed to know and observe her for so long.

Was he some kind of creepy stalker... or something even worse?

But even that didn’t explain how he knew those things.

The only possibilities she could think of were that he could read her mind or that he had somehow read her memories.

Because she knew herself well enough to understand that she would never reveal such details about herself to anyone unless she trusted them deeply.

And trusting someone that much was almost impossible given her nature.

Still, the idea that he could reach into her memories was terrifying. It would mean that nothing she had ever thought was truly hers alone.

Every calculation, every plan, every ugly thought she had ever written in that diary but never said aloud, he knew all of it.

Even every lie she had told him since meeting him at the academy, every little act she had put on while pretending to be a cute girl just to get his attention, everything she had done...

He had seen through it all and still he acted the way he did.

That alone felt terrifying but the problem was that some small traitorous part of her wasn’t terrified because somewhere under the fear was the thought that if he had seen all of it and had still sat across from her ordering cloudberry tart, then perhaps the facade had never been necessary at all.

She hated that she found that comforting.

As her thoughts ran wild, Aurelion caught her with ease before immediately turning around and running through the empty streets.

"What is happening, brother?" She asked him. "And what were you even doing in that cafe?"

Aurelion simply shook his head.

"I don’t know. I was there to grab a coffee when that spirit started manifesting, isolating the entire cafe." He paused before asking, "Did Zenith say anything?"

She didn’t say anything about how her brother was blatantly lying about it being a coincidence when she knew full well that he had followed her.

"No, he didn’t say anything either."

"I wonder why he jumped into the mouth of that monster, then."

Aurelion wondered aloud but he didn’t stop running.

From everything he had learned about Zenith over the past few days, he was certain of one thing, Zenith wouldn’t do something unless he was sure of what he was doing.

Meanwhile, Seles turned to look at the massive monster still following them with its slow-moving body, and only one thought crossed her mind.

"I hope nothing happens to you, Zenith."

Because despite everything he had said and shown her, she still had far too many questions that needed answers.

And he couldn’t possibly die before giving them to her.

***

[Zenith’s POV]

As my body fell into Octina’s gigantic mouth, I carefully avoided her disgustingly sharp teeth, each one capable of tearing me apart in an instant.

My goal was to separate the core she was using as a medium for her manifestation.

This gigantic octopus was one of Lily’s tamest summons in the future, when she had actually grown stronger enough to control her.

But at the beginning, she never listened to Lily’s orders.

I didn’t even know why Lily would summon her at this point in time, especially when Rwar was always there for her.

But one thing was certain.

Lily had somehow been overpowered by this damned octopus and was now being used by her as a manifestation medium.

That meant Lily was probably lying unconscious somewhere near the core of this gigantic creature, and all I needed to do was awaken her.

It sounded simple, until it wasn’t.

This octopus had one of the strongest internal defense systems I had ever seen, rivaling even Nyx’s at her peak.

But thankfully, she was being heavily limited by Lily’s low strength, so it was doable as long as I stayed careful.

Probably.

Otherwise, death was guaranteed anyway.

Soon enough, after somehow avoiding every tooth in my path and slicing through the ones I couldn’t avoid, I reached the stomach area.

It looked like a vast lake, except for the fact that it was filled with acid and the bodies of countless beasts and other things Octina had devoured.

Thankfully for me, the acid worked slowly.

Without any hesitation, I sprinted towards the left side of the stomach, where a narrow tunnel was located.

I knew the way by heart because, unfortunately, this wasn’t my first time in this place.

When we were still slightly weaker, we used to travel through the sea in my previous life. During those journeys, we often used Octina as a submarine because she could avoid the detection of many monsters in the deep sea, whose favourite dish apparently happened to be humans.

And her core was where we had built a small house to rest during those trips.

After all, she was somehow even larger on the inside thanks to some spatial mumbo jumbo that allowed her to digest much larger prey with ease.

But unfortunately for me, unlike the last time I had come here as a guest, this time I was an enemy who had decided to rebel instead of getting dissolved in her stomach like a good boy.

So, the moment I stepped into the tunnel, some muscular humanoid monsters with octopus-like faces emerged from the walls.

Their entire bodies were white.

They were her cells, the ones responsible for her defense.

Right on cue, I pulled out Kosetsu once again.

Because this wasn’t going to be an easy fight.

All of them lunged at me at once as I swung my sword, its fragmented blade separating into a larger arc as it cut down the first three that came at me.

The remaining ones adapted immediately.

Two of them merged into the walls while two ran along the ceiling, leaving the one two to charge at me from the front.

I lowered my body slightly, ready to reinforce it with vectors and launch myself at the first two before dealing with the ones on the ceiling.

But before I could move, the two that had vanished earlier suddenly emerged beside my legs and pinned them in place.

Fuck!

They could do that?

I had no idea.

This was my first time seeing them in action.

But there was no time to react.

The hands of the one coming from the front elongated into a weapon as it swung at me.

I barely managed to duck beneath them before swinging my sword at the ones holding my legs but before it could reach them, they vanished back into the wall of the tunnel.

Immediately, the two on the ceiling attacked me.

I was caught off guard as the one whose arms had morphed into a hammer struck me squarely in the center of my body.

Crack!

My ribs cracked slightly as my body was sent flying out of the tunnel and crashed back into the stomach acid.

"Fuck!"

I could accept that I hadn’t reached the level of some of the monsters in this world yet but I was a freaking Demon King in my previous life. I had defeated my fair share of powerful opponents and here I was getting beaten by a bunch of cells... even if they were cells of some primordial spirit.

As I cursed my own weak body, the smell of something burning suddenly reached my nose.

I looked down only to see the clothes covering my body burning rapidly.

The stomach acid that had been relatively tame earlier had intensified, eating through everything at an alarming rate.

I immediately jumped out of the acid and landed on the skeleton of some dead beast and thankfully it wasn’t too late as the acid had only eaten half through my clothes and some of them remained to save my dignity.

The cells of Octina were staring at me from within it without coming down as if the stomach acid was somewhere they couldn’t enter.

But I understood one thing...

This damned thing was going to be even more difficult than I had previously thought.