Night fell.

That meant the vampires were freed from the bonds of sunlight and could unleash their true power.

“Erika.”

“What is it, Satori-kun?”

Over the phone, Erika sounded gentle, kind…and most of all, triumphant. She would not wait until the morning. She would not give up her turn. I could hear it in her voice.

“It’s getting dark around here, but what do vampires eat? With that many of you, you’ll need a lot of supplies just for dinner.”

“Hee hee. Don’t worry. As long as we have fresh blood, we can survive in the wild or in the mountains or wherever else. Of course, eating hamburger steak and cabbage rolls like normal provides nourishment for the heart. So for the time being, I’ve ordered them to expand our forces while finding their own supplies. Of course, things might change once the vampires cover the entire city…Urp.”

“Um, Erika?”

“I’m fine, I’m fine. I’ll be back to normal after a few deep breaths. …I refuse to let Ayumi-chan beat me. If I work at expanding my stomach bit by bit, I’ll be able to shock you with how much blood I can drink.”

“You don’t have to compete over that and that isn’t what I’m looking for in a girl!!”

“By the way, what about your dinner, Satori-kun? I always take care of the cooking when mom isn’t around, so did you manage to find something? I’m honestly kind of worried.”

“Yeah. Ayumi and I ate barbecue together”

“What!? That sounds like so much fun! Why didn’t you call me!? Aren’t we family!?”

“Huh? I thought a clean freak like you wouldn’t like sitting outside with smoke everywhere and getting your hands all messy.”

“Satori-kun, it is being a clean freak that gives me such a clear distinction between what is and isn’t clean. Now, which is cleaner: letting yourself enjoy an event or refusing to take part due to sour grapes? And no fair! Noooo fair! Why is Ayumi-chan the only one that gets to be with you!?”

“Sorry, sorry.”

I moved the phone from my ear when she started yelling.

And then I said it.

“But this is all your fault.”

“…Oh?”

The cellphone signal could not carry an atmosphere or aura, but I still felt a squeezing at my chest.

But I didn’t care.

I had decided I would save the Swimsuit Cla.s.s Rep from the vampires. And I was willing to make a mess of the simulated Kukyou City to do it. So this was not the time to declare war. Erika had already done that when she captured the Cla.s.s Rep.

“I’m only saying this once, so listen up.”

“Okay.”

“Take the Cla.s.s Rep and escape to an elevated place. If it’s a building, get to at least the third floor. To be honest, I haven’t done the detailed calculations, so the higher the better.”

“Hey, Satori-kun. I don’t want to ruin this moment because my heart is pounding hearing my cute little brother sounding so cool, but I’m going to do it anyway. I don’t know what you’re about to do, but do you really believe you can defeat me? After my overwhelming victory during the day, do you really believe you can even touch me at night?”

“Didn’t I say I’m only saying it once? This is all wasted if the Cla.s.s Rep is caught in it.”

Yes.

Normally, she would have been right.

But…

The deluge of water pouring from the broken dam overturned all of that.

A giant reservoir of water in the mountains supported the city’s water supply.

I had gotten some help from Ayumi the zombie girl to take control of the dam. No, to destroy it.

It was obvious what would happen to the city downstream. The Weather Spheres meant to predict flooding were entirely useless.

“Satori…-kun!? Wait, don’t tell me…!!”

“Is the water already there? It doesn’t rush in as a solid wall. It will start rising at your feet, but the next thing you know, it’s several meters deep.”

I viewed the nighttime city from the mountain road, but then moved the smartphone from my face a little.

The aerial image from the drone showed the roads filling up with dark water in no time at all. The buildings looked like lines of square stones cutting across a pond.

In truth, the depth and speed of the water did not matter.

The main point lay elsewhere.

“Vampires can’t cross running water.”

“!?”

“So prepare yourself, Erika. A vampire’s strength comes from their twisted social structure with the queen at the top. You can’t take advantage of that if you’re trapped on separate rooftops. And it goes without saying that the water won’t stop the zombies from moving around the city.”

Our battle preparations were complete.

I had no more reason to wait, so I hung up and got to work.

“Onii-chan, where can we find a boat!?”

“This is a disaster prevention city! We can find one just about anywhere!”

Next to the roadside metal cases for fire hoses were identical sized containers. When I opened one and turned the valve, a rubber boat with an electric motor inflated like an airbag.

“More importantly, Ayumi, are you okay? You’re injured!”

“Hm? Why are you worried about a zombie’s injuries?”

She gave a quick wave of her b.l.o.o.d.y hand. She had been like this since getting back from the dam. I could guess that the workers had put up a valiant fight to prevent the entire city from being flooded, but it was odd that the top of the zombie side had been this badly injured. Was there something more to the dam?

She used a sewing set’s needle and thread to roughly sew up the wounds like she was repairing a stuffed animal.

“We need to hurry, Onii-chan. Time isn’t going to wait around!”

“Well, if you’re fine, okay. But be more careful next time! You’re a girl, after all!!”

“C’mon, you’re making me blush. Oops, my arm came off.”

“Ayumi, make sure you get thaaaaaat!!”

We placed the rubber boat on the water that was as dark as the sea at night. First Ayumi climbed on while continuing to sew and then I followed with the collapsible bike in my arms.

I hadn’t even thought about how to use one of these since they had taught us in school, but I managed to use the motor that doubled as a rudder to steer us along the great muddy stream and toward Kukyou City.

“How are we on zombies!?”

“I made some more at that campground and at the dam! Once there are enough of them, they’ll multiply like crazy on their own!!”

I used the aerial footage from the drone to steer the boat toward where Erika was. The buildings rising from the sunken city whooshed by on either side of us.

The pandemonium had already begun.

The vampires could not cross flowing water, so they were stuck on the building rooftops. Then the countless zombies rose from the water, climbed the walls, and swarmed the isolated vampires. Even if there were more vampires in all, the zombies outnumbered them on the individual rooftops. After that, they were helplessly devoured.

Wow…I know it’s not fair to judge zombies like this, but you certainly can’t call them smart…

“Good, it looks like they’re multiplying just fine. Go get ‘em, men!!”

“It looks like the drowned corpses and the ‘uninfected’ who aren’t part of either group can both be turned into zombies. But it also looks like we aren’t powerful enough to turn a vampire into a zombie or vice-versa.”

“That doesn’t matter as long as we can get back at our smug sister.”

We discussed the situation as our rubber boat raced across the dark water.

Using the drone, I could tell exactly where Erika was and that was thanks to one of the vampire’s major restrictions.

A vampire could not enter a house without permission.

Our home and public facilities like a school were exceptions, but she could not set foot inside any private property. That meant she was stuck out on the rooftop.

To her and the other vampires, the world was made up of separated square fields.

I just had to peer down at them with the drone.

The balance of power had been reversed in no time. The vampires were no longer a group centered on their queen, so a local difference in numbers was enough to defeat them individually.

“Onee-chaaaaan!!”

Ayumi shouted over the roar of the rubber boat’s motor.

We were right next to the rooftop where Erika waited.

A chapel bell tower was visible next to it, so it was not that tall a building.

We practically crashed the boat into the edge of the half-submerged rooftop. While I tied the boat on with a rope, my little sister climbed onto the roof and faced the vampire in a gothic lolita dress.

Erika had a servant on either side of her like bodyguards. Those two, Erika herself, and the forehead gla.s.ses Cla.s.s Rep were the only ones there.

I heard splas.h.i.+ng from all around us.

Five, ten, fifteen, twenty… More and more arms broke through the dark water and grabbed the edge of the roof. Then the zombies pulled themselves up. Ayumi’s forces looked like they were crawling up from the depths of h.e.l.l.

Ayumi jabbed a finger toward our older sister’s face and gave a shout.

“This is checkmate!! Okay, it’s time to pay the piper. Don’t think I’m going to forgive you if you apologize now!!”

“Don’t act so proud. This devilish resolve was definitely more Satori-kun’s style.”

“That doesn’t matter!! Onii-chan is mine right now!!”

“Oh, my. I’ll kill you for that one, little sister.”

“Fuguu!!”

The abandoned Swimsuit Cla.s.s Rep stared at me with blank eyes that said “awaiting instructions”.

I can’t stand that look anymore! You stupid simulator!!

“Hmm.”

Then Erika glanced over at me instead of Ayumi.

“So you’re willing to put this much of a fight for your precious Cla.s.s Rep? Even when it’s just empty simulation data being controlled by Maxwell? Yet you never seem too interested when the two of us fight over you in the real world.”

“Of course I’m scared!! If she finds out about that swimsuit dance file set, she’ll beat me more than just half to death! Ohh, I so don’t want her upset at me!!”

“I see, I see,” said Erika while nodding twice.

And then…

“…That really p.i.s.ses me off…”

“Eh?”

“Oh, nothing☆”

All of a sudden, she put on a bright smile.

“Now, then. Ayumi-chan, you tried to sound cool with your checkmate line, but let’s take a look at the exact situation here. Do you really think a vampire will be so easily defeated at night?”

“You think you’re so great, don’t you? Get her, men!!”

Wow, this little sister gets really carried away as soon as she has the upper hand!!

She’s hopeless! And when she was sobbing not long ago!

After the command from their evil ruler (or maybe that didn’t matter at all since they had no hierarchy), the zombies rushed in from every direction. Erika ordered her two servants out to stop them, but they were outnumbered. There were more than thirty zombies, so the two vampires were forced down onto the rooftop and then devoured.

That just left Erika.

Perhaps to preserve her dignity as a queen, she did not use the Cla.s.s Rep as a s.h.i.+eld.

“Hey, Ayumi-chan.”

“What!? I’ve never been happier, so I guess I’ll hear what you have to say!!”

“What do you think our original plan was?”

The zombies rushed toward Erika.

Unlike vampires, zombies were not organized. Ayumi had dashed toward Erika not to deliver the finis.h.i.+ng blow, but to grab the Cla.s.s Rep’s hand and pull her out of harm’s way.

We were finally reunited.

However, I could not just rejoice because a swarm of zombies was grabbing at Erika.

But this was the end regardless.

Once we had a result, the simulation would end and it would all be over.

Or it should have been.

Even as the crowd knocked her to the floor, my older sister looked my way and continued smiling.

That clean-freak was torn bloodily apart.

“Don’t worry. My wounds will regenerate unless they take out my heart.”

“…”

“And there’s no reason for you to feel sorry. I’ve been making progress in my own way.”

I finally felt a chill down my spine as I watched her expression remain unchanged even as she had more and more bites taken out of her.

“Ayumi-chan, why do you think I started off by focusing on the administrative inst.i.tutions like the police and the city council?”

“What are you talking about, Onee-chan?”

“Surely you didn’t think it was only so I could control the influential people and the information sources in order to send both the humans and the vampires against your zombies☆”

…What was this feeling?

Was there something more? How many new forms did this final boss have!?

“Vampire skills are a lot like a mutation. No one knows what skill you’re going to find. So if there’s one you want, you have to keep making more vampires and hope you get lucky.”

Vampire skills could be a number of things.

It could mean turning into a bat or a wolf and it could mean changing size.

But wasn’t there one truly inhuman skill?

One that almost overturned the definition of a vampire as a bloodsucker?

“Yes, yes. If you just want to kill a lot of people, then a Kallikantzaros or a Nelapsi would be fine. If you want to be more surrept.i.tious about it, then a Doppelganger or a Vrykolakas is more than enough. But a vampire that takes blood from the dead rather than the living is much harder to come by. I really must have the luck of a queen to have hit the jackpot today☆”

Erika never stopped smiling as the zombies pinned her to the floor and devoured her.

Conversely, Ayumi’s face paled.

And yet this should have been checkmate for her.

“I wanted a vampire that appears in old Polish literature. It can move during the day, it sucks blood from the hearts of the dead, and it can bite its own flesh in its coffin to suck the life force from its relatives. Of all the many legends, not many are quite this cruel.”

Her voice contained the joy of someone who had successfully hidden the perfect present and was now hiding it behind their back, waiting to reveal it.

“It is known as the Upior and it is said to ring a church bell and kill every single person who hears it☆”

My spine was flash frozen.

But Erika was not done speaking.

She had more to say beyond that secret weapon.

“Didn’t I tell you, Satori-kun? The Upior can suck blood from the hearts of the dead. After everyone within range of the church bell falls dead, she just has to turn them all into vampires. With the modern population density, that would be a thousand people? Ten thousand? It might even reach a wondrous hundred thousand.”

“That’s impossible… The entire city was flooded. Even if the bell rings, the Upior can’t pa.s.s over the water!”

“But! What if the order was reversed?”

“…”

“Eh heh heh. I said the Upior can move around during the day, didn’t I? Instead of her fangs, the Upior sucks blood using her long, skinny tongue that stabs people like a thorn. And didn’t I say I wasn’t taking over the police and the city council for no reason? I had tens of thousands of people gather in stadiums and theatres. Those are not the most hygienic environments, so bug bites are hardly uncommon. Yes, the Upior left her scars in advance. Hee hee. Why didn’t that cause a commotion? Because we released plenty of flying bugs to give people a nice excuse for themselves. The Upior could casually walk around biting them all while they were packed in like it was rush hour. And when the Upior bites a corpse, they become a vampire. So don’t you think the process could be reversed a little? And if it can…”

The vampires had originally revealed their ident.i.ty and attacked the people trapped inside the barricades. They had sucked their blood one by one, creating more vampires.

But they wouldn’t have been able to suck the blood of every last person in a stadium.

A lot of the people would have run for their lives.

But what if that had not been enough to save them?

What if they had only thought they were safe? What if they had only been allowed to go free for the time being and they had no say in their own fate?

“You can’t…” cut in Ayumi.

But Erika did not stop.

“The bell just has to ring once and every last person we put in a ‘reservation’ for will die and immediately turn into a vampire thanks to the Upior’s mark. Doesn’t that sound like it work? Hee hee. Unlike the rest of us standard vampires, the Upior doesn’t have to suck a lethal amount of blood. Since the target is already dead, it doesn’t take much blood for the effects to kick in. Plus, if we turned all of the survivors into vampires during the day, the sunlight could have wiped them all out and we would need a further stock of humans to continue on. Now, a question, Satori-kun.”

“You can’t!!”

“The Upior could safely move around during the day and I sent her to a total of eight civilian fortresses such as stadiums and theatres. She probably made her ‘bug bites’ on almost three hundred thousand people. So what percentage of that will turn into vampires at the ring of this bell?☆”

I did not have time to give an answer.

Ayumi tackle the Cla.s.s Rep and me into the dark and cold water.

As soon as we hit the thick wall of water, a heavy ringing shook the world above.

In addition to the standard traits, most vampires have a special skill. These are most likely mutations created from a mixture of the victim’s own traits and the skill of the vampire that bit them. One group is attempting to establish a link between this and the chromosome damage caused by cell death while the blood is being sucked out, but that will likely end in failure.

Their fighting spirit will be broken when they try to physically explain how that leads to shrinking one’s body or transforming into a wolf or a bat.

I have seen quite a few samples, but one of them stands out as the worst.

The Upior.

That vampire has its origins in Poland. The worst part is the fact that it has several ways of attacking people without biting them.

The worst of those is a church bell.

The Upior can remain active during the day, but they will also sneak into churches to ring the bell during the dead of night. Anyone who hears it and whose age is close to the Upior’s when it died will be killed.

You might think they are somewhat lucky to only be killed.

You might think that is better than becoming a vampire.

But that isn’t the case.

The Upior has a wide variety of abilities. Not only can it move around during the day, but it also rings a bell at night. Those traits are complete opposites.

And there are further legends.

While most other vampires wander to suck the blood of the living, the Upior is said to prefer sucking blood from the hearts of the dead.

If the Upior caused devastating damage to a village or town in a single night and then sucked the blood of the dead – in other words, if it turned the dead into vampires – the living who had escaped the initial damage would be swallowed up by the swarm of monsters. They would have no way to defeat the powerful vampires surrounding them and they would be overwhelmed by the pure numbers.

Can we really defeat a monster like that?

That vampire has strength, intelligence, and numbers. What human advantage is left?