My Vampire Older Sister and Zombie Little Sister

Chapter 0

[Self Record] Basic Information [Leviathan's Report]








...There are too many of them. Some of them are in multiple slots. And alternate names like Satan and Lucifer just make it more confusing. There are multiple candidates because the situation changes depending which version of European theology you are looking at, but the dignity of the title "Demon Lord" fades a bit when their numbers reach the double digits. Then again, this is a theory put together by theologians to conquer the fear of demons, so that may be the right way of going about it.

Chapter 0

"Huhh? Taori-san, did you take someone in again? Well, not that I can complain when I'm a freeloader too."

I was a mess.

I had been thoroughly beaten.

But not by anyone out there in the world. By my own ugliness.

I still felt depressed as a woman in a white dress and cardigan, who had once been my mother, led me to a high-rise apartment building I had never seen before. Instead of blending into the similar buildings of a residential district, it stood out from the coastal shopping district and would have made a good landmark. As soon as we stepped inside one apartment, we were greeted by a confused voice.

"You really do like this kind of thing, Taori-san. Have you already forgotten how mad the landlord was when you brought back that big dog even though this place doesn't allow pets?"

It was a flashy blonde girl in a champagne-red dress who spoke to my mom. I didn't know what to call her hairstyle, but the silhouette of her head looked like it was part of a revolutionary new trend in flower arrangement. I had never seen the real thing, but she looked like the cabaret girls I had seen in dramas. She had a lot of accessories on her hands and around her neck. I doubted she was in high school, but she looked a little young to be in college. Her flashy appearance may have been leading me astray, but I had difficulty grasping her age or figuring out how formal to act around her.

My mom, Magatsu Taori, silently nodded.

"You can tell?"

"Well, yeah. He's in some kind of trouble like me, right? Besides, do you have any idea how late it is? You were only just freed, so I know you aren't about to bring a young boy home with you for no real reason. That would be a waste."

The cabaret girl waved her hand dismissively before continuing.

"I'm Himatsuri Asami. Nice to meet you, runaway boy."

"Oh, um, uh."

Who was she?

My mom had supposedly been trapped below an abandoned hospital for more than three years, so had these two recently met and really hit it off?

"What? You aren't going to introduce yourself?"

"I'm...Amatsu Satori."


This Himatsuri person curiously repeated my family name. She was clearly wrinkling her brow. She apparently knew my mom well enough to be familiar with her family situation.

Which would include that she had returned to her maiden name after the divorce.

"Oh, well, this is quite something... T-Taori-san? Did you do something rash!?"

"I didn't take him away from his home. I just happened across him looking like this, so I was worried..."

"That excuse will only work with your friends! Oh, honestly. I'll contact my family lawyer, so you just be honest about everything that happened. I'll get this straightened out, but don't you know how messy child custody issues can be!?"

Himatsuri-san began mussing up her own impressive blonde hair and then called someone up on her smartphone. Despite her flashy appearance, she may have been the sympathetic type who would help anyone out with their problems.

And a family lawyer? Did that mean she was rich? If she was living here, she must not have had her own cook or driver, though.

My mom watched the cabaret girl(?) walk out onto the balcony with the phone and then she laughed and turned toward me.

"Don't worry. If Asami-chan says she'll straighten this out, then she will, so you don't have anything to worry about."


"You don't have to tell me everything. Just stay here for as long as you need to and head home once you think you can."

That was extraordinary.

But that was why I couldn't help but wonder why she would go this far.

And she must have sensed the doubt in my face because she relaxed her shoulders and whispered to me.

"It's best if you don't understand. Especially at your age."

Of the few rooms, she showed me to the living room and reached for the TV remote.

"Defeat 100 comedians with your trademark gag? Easy! I've made it 20 years with one impression! Dwah hah hah!!"

"It has been revealed that the military was involved in the largescale infrastructure damage done by the slime Archenemies in Las Vegas, and it is looking possible that the entirety of Congress will resign..."

"Marine Biology Quiz! This week's theme is sharks! They get a bad rap, but most of them aren't all that violent."

She flipped through a few channels, but she probably wasn't looking for anything in particular. She was just trying to distract me, so she was focused on finding something calming to watch.

"Given the time, you can think of it as a late night snack, but do you want me to fix you some pancakes, Satori-chan?"


"You liked them, didn't you? With ice cream on top? Assuming Asami-chan didn't eat it all, there should be some vanilla left in the freezer."

At first, I had no idea what she was talking about, but she wasn't remembering wrong. I vaguely recalled eating that a lot when I was little.

Was our family still frozen in time in her memories? If so, that was sad. She had not made a new family or started on a new life. And it had happened because I hadn't gone with her after the divorce.

She slowly removed her cardigan and called out to the balcony.

"Asami-chan, what did you do with the bath?"

"Right, right. So make it top priority! ...Yes? I left the bathwater in the tub. I thought you would want to take a bath when you got back."

"You heard her. I'll reheat the water, so take a bath. You're exhausted, aren't you?"

"Eh? But...?"

"The basics of life matter. When there's a weight on your mind, satisfying your body's needs is the best first step. Or do you want to take a bath with your mom like old times?"

"Okay, okay, let's not make this more complicated than it already is!! I can hear everything you're saying!!" Himatsuri-san stormed in from the balcony and then pointed straight at me. "There's only one rule here. You can cause Taori-san all the trouble you want, I'm in no place to criticize you for that. But make her cry and I'll hit you, no matter how much she tries to stop me. Understand?"

Since she wrapped her expensive-looking watch around her palm instead of forming a fist, she must have been used to getting into fights. Was she planning to scratch me with the watch's face? When I nodded several times, she smiled. It looked like she had accepted me as one of them.

"That's fine then. I'll pick a fight with the world too."

I was then pushed on over to the changing room. At this rate, I started to think I really would be served pancakes with vanilla ice cream on top.

Once alone in the changing room, I looked in the mirror and pulled out my smartphone.


"Sure. You have 34 missed calls, 20 emails, and 58 text messages. How will you respond?"

"Sorry... Can you just ignore those for now?"

"That is a disappointingly pathetic response, but I suppose you are not hopelessly pathetic as you did not ask me to erase them."

I was well aware how horrible and lame I was being here.

Las Vegas had been taken over by the slime Archenemies we called gels. It had been destroyed by the air force bombing meant to suppress the gels. I had saved the people swallowed by the gels, but that was all. Behind the scenes, it had all been connected to the tickets for an ark known as Absolute Noah. My stepmom, Amatsu Yurina, had given tickets out to the people who had been selected by the machines because they had top priority “on paper” and she had used that to wipe them all out so they would not take up the spots needed for the people who truly deserved to survive. She had intentionally caused a disaster, given those black-hearted people false arks, and made sure they could not hope for anything more than that.


So what?

What had I done when I learned the truth? I had thoroughly criticized my stepmom, but I had failed to get her to say she wouldn’t do it again. I couldn’t even get her to apologize.

No, I had known from the beginning that nothing I said would draw out the words I wanted to hear.

I had known that, but I had still hurt my family.

Issues of justice and stopping that grand plan had been second in my mind. All I had done was throw my frustrations at her. And then I had run off, made sure she couldn’t find me, and then made myself a burden on my biological mother who I had supposedly parted ways with already.

…Is this the kind of person I wanted to be?

What kind of person had I dreamed of being in those crayon drawings on construction paper when I was little?

“I have already made my judgment of you, user. You are pathetic but not hopelessly so.”

“What’s the difference?”

“At the time, a few different options were available to you: get into a fight with Madam Amatsu Yurina and drive her out of the house, leave the house yourself, or pretend it had not happened.”

Maxwell spoke through a series of social media speech bubbles.

“You could not keep quiet about this unreasonable world, but you also could not take away a family member’s home. So you left yourself. …That means you are quite fragile, but with a strong sense of justice and kindness. Thus you are not as hopeless as those who let their sense of justice narrow their vision to the point of swinging their fist in their own home.”

Did that mean I was walking the same path as my mom who had left our home after the arguments with my dad progressed too far?

“As a result, you alone have lost everything. Even though other options were available, such as turning your back on justice and laughing, or wielding your justice to threaten her. …So you should be proud of your decision. I am more than willing to support my pathetic user in this.”

“Is that so?”

I finally felt like I could see a slight smile on my haggard face in the mirror. A bit of flattery could really change your outlook on the world. That seemed pathetic, but I couldn’t just sit around.

“Maxwell. Send an email to Ayumi, Erika, and the Class Rep’s phones. Tell them I’ve just run away from home for a bit so they don’t need to worry.”

“Warning: I believe anyone who reads that will see it as something you were forced to write after being caught up in some kind of trouble.”

“That’s why I’m telling you to do it instead of me. They’ll be relieved to know my inspector is with me.”

“…I am most concerned about your monstrous sisters’ jealousy. It makes me feel like I have been caught up in an argument over what one thing you would bring with you to a desert island.”

I placed a towel over the smartphone on the washing machine, stripped off my clothes, and walked to the bath. The tub seemed larger than at home. Based on the control panel, it seemed to be an IoT appliance. It was apparently connected to the internet so it could heat the water according to the schedule on your phone. …But that seemed dangerous. Couldn’t a cyber attack start a fire or give you carbon monoxide poisoning? I thought about having Maxwell check it over for vulnerabilities later. Or would a white hacker like Anastasia enjoy doing that? It was probably best to ask the expert. And she was bound to do it if I presented it to her as a competition with Maxwell.

I used a washtub to scoop up some bathwater and washed away my sweat as I thought.

Whatever I was doing, it had to start tomorrow.

I had no idea how to solve this problem, but I couldn’t just leave it like this. The Calamity would supposedly destroy the population of the earth and Absolute Noah was the ark meant to survive it. I couldn’t avert my gaze from that.

With that in mind, I entered the tub feet first.

And as soon as I did…

I fell.

Where to? Into the bathwater filling it, of course.

I instantly sank in deeper than my head. I couldn’t breathe, intense pain shot through my eyes, and the heat of the water seemed to reach deep inside my head. I had no idea what had happened. I initially thought I had stepped on the soap and flipped over, but that wasn’t it. I was clearly still upright as I sank. …So was there no bottom!? It was like I had been thrown into a deep pool!

“Cough, cough!! Cough!?”

When I flailed my arms and legs around, I was clearly able to swim. Like I was trying to reach the top of an old well, I swam up in search of air. I finally parted the surface of the bathwater and filled my lungs with air, but the abnormal situation was not over yet.


The bottom of the tub was back to normal. I could feel the smooth plastic supporting my butt.

But the room was dark and had no power. I could only observe my surroundings thanks to the bathwater.

It was bizarre.

The water was glowing with a sticky blue light, like it was glow-in-the-dark paint. The pale light came from both the water in the tub and the drops on the tiled walls. The mirror on the washing area’s wall had some kind of strange pattern drawn on it.

It suddenly hit me that this light was a lot like the ocean covered in sea sparkle I had seen in a documentary.

“What the hell is this?”

I crawled out of the tub and found my wet body was glowing the same color. It was more embarrassing than creepy. I dried myself off with a towel and then returned to the changing room.

I could hear large raindrops pounding on the wall.

? That sounds like a typhoon. But it was such a clear starry sky outside…

“Maxwell. What is going on, Maxwell?”

I threw back on my clothes and reached for the smartphone covered in the towel on the washing machine.

But there was no response. No matter how much I tried, it would not connect to Maxwell. It had no signal anymore, making it entirely useless.

So was this not just a power outage or tripped breaker?


I thought for a bit and then realized something.

Something was written on the mirror in front of the sink. But it didn’t look like a text made up of meaningful characters.

Come to think of it…

I opened the door to the bath again. Sure enough, the same pattern was on the washing area’s mirror.

What was this?

I returned to the changing room and moved my face in close to the mirror. A few lines were intersecting. Were those supposed to be three-way and four-way intersections? It looked like a crude, hand-drawn map and one corner of an intersection had an arrow pointing to it.

Something changed as I watched it. As if the water on the mirror was dripping down, more blue glow-in-the-dark light was added.

“today’s exit”

That was all.

What was this? Had it happened on its own? I checked the bath and found the same writing on the mirror there. That was ridiculous. So was it not just a coincidence? Was there really writing here?

It felt like I had been thrown inside a simulator or a dream.

Ever since I had so unnaturally fallen into the tub, something had gone wrong with the world.

“Mom. Yes, mom.”

She would know something. …Wouldn’t she?

Either way, I didn’t have to worry over this alone. With that in mind, I threw open the door from the changing room to the living room.

Just then, a bunch of night rain slapped me in the face.

There was no room there.

It had been torn away like the aftermath of an aerial bombing in a war movie, so I simply saw a stormy night in front of me.


It made no sense.

What was I even looking at?

“Mom! Himatsuri-san!?”

I knew yelling was useless, but I still desperately hoped I would hear a voice in return.

How many floors up was this?

How had an entire room – no, an entire chunk of a high-rise apartment building – been torn away like this?

I could see my hometown of Kukyou City through the stormy rain and winds, but it wasn’t the city I knew. The dark scene was filled with a blue glow. This wasn’t just your average increase in water level. This flooding was easily as tall as a school. I couldn’t tell where the roads began and ended and I could only see the taller buildings sticking up from the dark water.

What had happened to my mom and Himatsuri-san?

And what about the others in the city? Like Ayumi, Erika…dad, and my stepmom!? Or the Class Rep next door!?

“Max-…no, that doesn’t work!”

I had never thought I would feel so forlorn just because my smartphone had lost its connection. I couldn’t share this absurd situation with anyone and I had to carry it alone. I just wanted to call someone I knew to know they were all right.

“A phone…”

As my mind nearly strayed from reality, this one desire kept it grounded.

“That’s right. I need to find a working phone.”

One corner of my mind rejected that idea with cruel rationality. What good was finding a home phone? A really old phone would be one thing, but modern multi-purpose phones needed more than just the phone line to power them. Everything was dark, and if that meant a blackout, I wouldn’t be able to use the phone. So there was no point in finding one.

But most of my mind refused to be so rational. It wanted to find a phone so badly.

The living room was almost entirely missing, so only a wall and a bit of floor remained. It would be suicide to walk along that 10cm surface during a storm and with only the wall to hold onto. I knew that, but there was a phone right over there. I could see that normal device there.

So I started to take the first step.

But I never completed it.


Because of the giant shark.

A shark rivaling a submarine in size broke the roiling water’s surface.


That snapped me back into reality.

The most insane sight yet reminded me of the very real possibility of death.


I had no idea how many floors up the water had risen, but the shark that leaped out of it had to be more than 30m long. It used all of its muscles to make the jump. I almost stared spellbound at the dark tunnel that was its maw, but then I pathetically fell backwards.

I fell onto the wet changing room’s floor.

And the elegant arc of the shark’s jump took it directly above me. It was like a head-on collision with a semi-truck pulling a large container. With a sound far louder than the storm or lightning strikes, the surviving boxy shape of the changing room was torn to pieces and swept away into the storm. The walls and ceiling were smashed up in no time. That thing didn’t even worry about the building walls. In hindsight, I realized the edges of the living room’s surviving wall and floor had been terribly jagged.

Was that it?

Had that thing done all this?


I didn’t have time to think about it. If it could destroy walls and ceilings when it attacked, there was no point in holing up in any kind of shelter. It knew I was here. If the next attack broke through the wall, I would have my entire body eaten and it would be game over. It could even tear down the entire apartment building.


Still in my clothes, I ran from the broken changing room to the bath. There was a window on the wall bordering the tub. I threw open that window and looked straight down.

The height made my vision waver.

But then I heard an incredible destructive sound directly behind me. In fact, I felt the heavy sensation of something stabbing into my back.

Was it one of the shark’s teeth? No.

I would have been bitten right through had it been that.

It was probably a piece of the wall that had broken off during the second attack on the changing room.

But that didn’t matter.


I had trouble breathing and I lost my balance like I had been shoved from behind while standing on the edge of a cliff.

The open window was right there.

I suddenly remembered that this was the 8th floor.

At the same time, I was thrown out into the blowing wind of the stormy night.

I must have screamed something, but I don’t remember what.

I helplessly fell about three floors and was dazed by a powerful blow to the face.

Not the ground, though. That would have killed me instantly.


When I got my soaked face above the salty-smelling water, I found what I expected. I had fallen into the sticky blue glow of the water flooding the city. I struggled against the powerful current and somehow managed to grab onto a roadside tree that was almost entirely submerged. It had to be about 4 or 5 stories tall.

But the water was that shark’s home ground.

I would be killed if I stayed here. Wasn’t there anywhere I could go to get inside? A balcony or an emergency staircase!?

I felt a chill on my spine as I looked around.

Then I saw something.

Every last one of the building windows above the water level had the exact same pattern on them, like a wall covered in identical posters. It was drawn out by the same blue glow I was drowning in. No, it wasn’t just a pattern. It was a map. It was a crude map without landmarks that looked like a kid might have drawn it. It had three-way and four-way intersections and one corner of a four-way one had an arrow pointing to it. And what looked like letters of the alphabet provided the one and only label: today’s exit.

“What am I supposed to do…?”

It took me a while since everyone relied on map apps these days, but I realized I did recognize that map.

I couldn’t see the roads or traffic lights with this flooding, but it was near my mom’s apartment. It was at the corner of a four-way intersection. I looked around and did indeed see something there. While everything else wetly glowed with a blue glow-in-the-dark light, this one spot shined with the light of a red-hot metal.

Was it…a door?

It was on a bowling alley. A strange metal door was directly attached to the wall without bordering anything else. It was probably meant for use with a firetruck’s ladder, but with the flooding, it looked like I could reach it if I swam directly to it.

And I didn’t have time to spare.

The powerful current didn’t give me time to think. As soon as my fingers were torn from the top of the nearly-submerged tree, I was swept away. Luckily, I was taken toward the orange glow.

I sensed a great pressure behind me.

That gigantic shark had found me. I could clearly tell that, but I couldn’t bring myself to look back. I hadn’t checked, but I could tell all too well just how accurately it was swimming toward me in this current. I was too afraid to just let the current take me, so I began an awkward crawl by mimicking what I had seen in the past.

What was this about?

What did that door mean?

I didn’t know, but I couldn’t stay in the water. I swam and swam and swam until I reached the metal door attached to the smooth bowling alley wall. I grabbed the knob, opened the door, and climbed in like I was a seal in an aquarium.

Just then, the entire broken city vanished like it had all been an illusion.


The pleasant sound I heard was probably someone in the alley getting a strike while playing late into the night.

I looked back and saw no blowing rain, no flooded city, no blue light…and no giant shark. I only saw the stillness of the night and the fact that this was definitely five stories up. With no water below, it was all over for me if I fell.

I stuck my head out through the metal door on the wall and saw my mom’s apartment building. It was not even 100 meters away. And it had of course not been destroyed.

What had all that been?

…If it had been a dream, then why wasn’t I collapsed in the changing room or bath?

I had definitely changed locations and I was soaking wet, although not glowing blue.


And I felt a dull pain in my back. A piece of broken wall had hit me when that shark destroyed the changing room.

If that wound remained…

Would I have lost my life if I had died in that shark attack?

I couldn’t explain my presence in the bowling alley without having paid, so I descended the emergency stairs and made sure no employees saw me as I left. Then I returned to my mom’s apartment.

That had not just been a dream.

It felt like there were two worlds and I had passed between them for some reason.

“Was it the bathwater…no, just water in general?”

I made sure to avoid the puddle below a streetlight as I said that.

That was how it had started. I had gotten into the tub, but found it too deep to stand and nearly drowned. Then as soon as I had gotten my head above the water, everything had changed.

It was like diving into the moon floating in a lake at night.

How unrealistic could you be?

Should I just laugh it off like that? I had been inexplicably moved from the bath, I was soaking wet even though it wasn’t raining, and I had a dull pain in my back, but should I still write it off as me “imagining things”?

Since this was a shopping district, the first three floors of the high-rise apartment building were made into a small shopping mall. The first floor bordering the road was lit up especially bright since it contained a burger shop and a convenience store. The night-shift worker looked bored behind the register. I only mention that because this peaceful scene made it hard to believe a great torrent of water had flowed through here just a bit ago.

The parking lot was underground and used turntables and elevators. The entrance for residents was also in a more out-of-the-way location. That entrance used a simple autolock, but when I typed in the room number, it connected me to my mom.

“Eh? Satori-chan, how did you get outside?”

She was confused and she must have gone to check in the changing room and bath. After that, she unlocked the front entrance for me.

It seemed I had not just been sleepwalking and invented some convenient memories to explain it.

If I had walked through the bath, the changing room, and the living room to reach the front door, my mom or Himatsuri-san would have seen me. But there was no other way to leave that 8th-floor bath. …And yet here I was walking around outside.

Something wasn’t right.

I was caught up in something.

But what was it? What did that giant shark and flooded city mean?

The elevator arrived before I could find an answer.

Surprisingly, Himatsuri-san was riding it.

She clenched her fist and winked.

“Make Taori-san cry and I’ll hit you. I explained that rule, didn’t I?”


“Well, you’re fine for now. So why are you so wet? And you smell salty. Is there a fishing spot around here? This is along the coast, but surely you weren’t out on the beach or embankment.”

She had apparently come down to meet me. She did not get off the elevator and must have planned to make a U-turn right back up.

The sea smell must have been strong in the enclosed space.

But then I noticed the floral scent of shampoo or conditioner coming from Himatsuri-san as she turned her back to look at the floor counter. She had likely used a dryer on her hair before preparing that hairstyle, but the skin of her visible nape was somewhat flushed.

…Had she taken a shower?

But when my mom had asked about the bath, she had said she “left” the bathwater in the tub. That sounded like she had already taken a bath before my mom got back.

Not that it really mattered.

The problem facing me was more important, so I muttered to myself.

“Sigh. What was with that giant shark?”

“Sigh. What was with that giant shark?”


Himatsuri-san and I both frowned and then exchanged a glance.

Why had our voices harmonized there?

Did that mean she knew about the giant shark?

She looked like she was wondering the same thing and my expression had to have been the same.

“You mean…”

“…You too?”

Our surprised comments were followed by a soft electronic tone. The elevator had reached the destination floor and the doors slid open.

[Self Record] About Sharks [Leviathan’s Report]

The largest of the fish.

The fierce species are most well-known, but the majority of them only eat small fish or plankton and the so-called “man-eating” varieties are extremely rare.

Setting aside their actual classifications and behaviors, the general public thinks of the great white when it comes to predators and the sturgeon[1] when it comes to prey.

Ironically, this entirely changes if you include marine mammals as well.

The violent great white shark cannot match the size of a whale or the ferocity of an orca.

Thus, the shark is the symbol of the strongest within a limited environment. For example, the king of a ring in which everyone is divided into different weight classifications cannot win in a no-rules street fight.

Sharks cannot defeat mammals.

Thus it may be envy that leads them to so persistently target humans.

Download the ebook

Volume 5