Mash-up Anime World: Creating the SCP Foundation to Contain Anomalies

After Kaguya's detailed explanation…

Hayasaka Ai's expression grew increasingly strange, until she was finally staring at Haruto with a frosty, ice-cold look.

That gaze—like she was looking at trash.

Maybe it'd excite certain people with specific interests.

Of course, Haruto only felt a chill down his spine.

Following her gaze back, he saw that it was Hayasaka Ai.

Haruto immediately understood most of the reason.

Given his earlier behavior, if one didn't understand the nature of the succubus girl, it'd definitely seem like the act of a pervert.

And Haruto wasn't thick-skinned enough to shamelessly say:

"She's not sweet enough, so I'm feeding her some deoxyribose."

…That kind of line.

Their eyes met, and Haruto immediately started to defend himself.

Haruto: "It's just part of the project's characteristics! It's not like I wanted to do it!"

Hayasaka Ai: "Go explain that to the young lady!"

Haruto: "Uh… I'll go check the containment site."

Hayasaka Ai: "Don't run, you trashy president!"

In the end, under Hayasaka Ai's complicated gaze, Haruto fled.

Meanwhile, Hayasaka turned back—only to find her young lady staring at her curiously.

Hayasaka Ai felt a massive headache coming on.

Her young lady was still so innocent that her knowledge of the opposite sex basically stopped at kissing leads to babies.

Sighing deeply, Hayasaka leaned down and whispered a scientific explanation into Kaguya's ear.

Kaguya's face grew redder and redder, steam practically rising from her head.

[Shinomiya Kaguya.app Not Responding]

She completely froze.

In that moment, Lady Kaguya pushed open the door to a new world.

In that moment, she matured a lot.

On the other side, Haruto had already returned to the Foundation site. The succubus girl's containment was proceeding in an orderly manner.

All male staff within the site had been sent off to the Central Garden of Life by the female staff, kept far away from the containment level.

This left the men a little confused—and very curious.

When Haruto arrived, he saw a group of male employees gossiping in the Central Garden of Life.

He gave a small smirk and walked over.

"The new containment subject causes cognitive hazards in men. Best not to approach her room. Of course, if you'd like to test your cognitive endurance, feel free to check her out. For those with such... robust spirits, the Foundation rewards them with a Tomie Cognition Training session."

Upon hearing that, the group of men instantly lowered their heads.

Tomie Cognition Training? That's pure torture!

Nope, not worth it.

Just like that, their curiosity vanished like mist.

Seeing this, Haruto nodded in satisfaction.

Afterward, he went to check on the succubus girl's containment chamber. Since she was cooperating with the Foundation, she had been granted certain privileges.

She could request non-dangerous items to be added to her room.

But she didn't ask for anything special, just a few newspapers.

Coincidentally, her containment room was right next to the "Invisible Friend" (SCP-126).

So, Haruto simply had the Foundation install a telephone between the two rooms. This way, the two girls could chat during their downtime.

While the succubus girl didn't show interest in much, literature was a fairly universal topic.

Chatting about books wouldn't bore her—in fact, it'd help both projects maintain a positive mental state.

Next, Haruto prepared some food for the succubus girl.

...Details omitted.

If they didn't do it this way, the Foundation would have to make an agreement with an external energy bank...

So it was better for Haruto to handle it himself. It's just a few cells anyway.

After wrapping that up, Haruto prepared to leave the site. But on the way up from the containment level, he ran into a familiar face—

Wait, no. A familiar ghost.

Kibutsuji Muzan was being escorted to the experimental floor, ready for testing. At this point, Muzan no longer carried the air of the once-mighty Demon King.

The endless inhumane experiments had left him visibly weak and worn out.

As they passed each other, Muzan spotted Haruto. A flicker of flame returned to his otherwise numb gaze.

"You… damn you humans… What do you even want…? I was so close!"

Muzan's voice was raspy, filled with bitter unwillingness.

Haruto paused.

As the origin of anomalies in the Demon Slayer world, Muzan certainly had his abilities.

But becoming the "ultimate lifeform"…?

He was still far from that.

Seeing Haruto stop, Muzan kept shouting, driven by his obsession,

"If I had just found the Blue Spider Lily, I could have become the ultimate being! I was so close! Just one step away! Where the hell did you humans come from?!"

Haruto nearly burst out laughing.

A demon's biggest weakness is sunlight.

The Demon Slayer Corps' long battle with Muzan wasn't thanks to Breathing Techniques alone.

It was the Nichirin Blades—crafted from a special ore that absorbed sunlight.

Without those, humans couldn't even hurt demons.

If demons could overcome their sunlight weakness, they'd essentially be invincible.

And the Blue Spider Lily? It really could eliminate that weakness.

Too bad…

"By the way, you probably don't know where the Blue Spider Lily actually grows," Haruto said.

Muzan's eyes widened, staring intently at him.

He'd spent a millennium searching for it.

Created the Twelve Kizuki, turned countless people into demons. All for the same reason—boost the search effort for the Blue Spider Lily.

The Demon Slayer Corps? Just a side event.

Now that Haruto brought it up, it reignited that buried obsession.

Muzan stared at him, desperate for more.

Haruto chuckled and continued,

"Actually, Blue Spider Lilies are pretty common. Probably grow all over some mountains. Kamado Tanjiro—oh wait, you don't know him. He's a descendant of Yoriichi Tsugikuni. His family used to eat Blue Spider Lilies as veggies. I could ask him how they taste later."

Muzan stood frozen, stunned.

Then the once-feared Demon King burst into a hysterical breakdown.

"Impossible! I searched for centuries! I've crossed every mountain and river! I spread demons everywhere to search endlessly without rest! If they were so common, how could I have never found them?! This can't be real!"

Haruto shrugged.

"Oh right, I forgot to mention—the Blue Spider Lily is common, but it only blooms under specific conditions."

Muzan immediately fell silent, eyes locked on him.

Even if he had no chance of ever obtaining it…

He had to know the truth. That obsession had driven him for a thousand years.

Haruto smiled.

"The Blue Spider Lily only blooms at noon, when the sun is at its brightest."

His words echoed through the corridor.

Muzan's monstrous expression faded into emptiness. He collapsed inside the containment box, utterly broken. The once-proud Demon King was now nothing more than a hollow husk.

His obsession with survival—now a cruel joke.

A millennium.

A whole thousand years.

He had spread the demon curse, taken countless human lives, all to live.

To become the ultimate being.

Yet the Blue Spider Lily, the key to that dream, was no rare treasure. It was just a common flower… blooming at a time he could never see.

Demons, fated to never coexist with sunlight, could never witness a noontime bloom.

Muzan, completely shattered.

Until now, even as a test subject, he still clung to life.

No matter the pain or suffering, he had that one obsession.

Now, that obsession had crumbled.

Haruto only shrugged again and signaled the Foundation staff to proceed with testing. Whether Muzan broke down or not didn't matter to the Foundation.

He was just another experiment.

Haruto only said all that for the sake of the countless humans killed in the Demon Slayer world.

To collect the debt.