It was an abrupt event.

In the way a drop of water falls, I was born into this world. At that moment, my consciousness cleared and I opened my eyes for the first time.

“Wh … what is this place . . ?”

Now that I was aware of my surroundings, I could clearly tell that I was lying in a stone pool of warm water. No, not water; it feels sticky, but it doesn’t make a sound when I move. I could tell that this was a very strange liquid. When I pulled myself away from the warmth of the liquid, I realized I was in what appeared to be an old, abandoned house. The narrow room was about the size of three tatami mats, and in the center was the mysterious pool of liquid. Aside from this, the room was completely empty.

Hmm . . ? Three tatami mats . . ?

I understand the measurements of three tatami mats, but I do not know where this understanding comes from.

When I looked down at the surface of the pool, a boy with a common-looking face was reflected. A boy . . ? I hesitantly touched my face, watching as the reflection did the same. I feel that this ten-year-old face doesn’t suit me.

And, also … how am I able to recognise this face as about ten?

<< You seem to be confused about various things. >>

Suddenly, a voice echoed inside my head.

“Who are you!?”

<< I am the System. I will guide you. >>

The voice in my head sounded young, like a child.

<< If this had been done properly, your birth would have reset your mind. However, you appear to have retained your previous knowledge. >>

Previous knowledge … does that mean, knowledge from a previous life?

It sounds like someone from an RPG … a role-playing game? Is that also something from my previous life?

<< It would be better for you to develop a little more, but you do not have time to spare. >>

I wonder why I don’t have much time.

Perhaps I’ve been born during a time of crisis and the world is facing certain destruction. I was probably created to be a Hero and defeat the Demon King.

<< You have the right idea, but that is not quite correct. >>

Oh? Then what am I?

<< The Devil. Many monsters are going extinct; before they die out, it is your responsibility to save them. >>

… … ?

Devil . . ? That means I’m the Demon King, right!? The Demon King who laughs wickedly while killing innocent humans, am I really such a thing?

<< The role of the Devil is not to kill humans. Some Devils do so as a hobby, but your real purpose is to protect monsters. >>

No way … I can’t believe I’ve become the Demon King …

<< The world is indeed in a time of crisis. The heroes have become too strong; the balance between humans and monsters has collapsed. Humans have begun to fight one another and are self-destructing. In order to prevent this, you must restore the balance. >>

Oh, is that so … I’m so shocked I can barely understand the situation.

<< Because of your previous memories, you must find this difficult to accept. >>

That’s right, but … I don’t feel like I could accept this even if I didn’t have any memories.

It seems likely that soon I’ll wake up and return to a normal life working for a company. A company … I can’t quite recall, but I wonder if I used to work for a company.

<< Yes, you had a normal life and worked for a company. You were entirely ordinary, but you happened to die prematurely. >>

I wonder why being called ordinary like that is a little painful …

Why was I chosen to become the Demon King?

<< To put it simply, it is because you were so normal. There would be no meaning to your existence if you run off to kill humans just because you’ve become the Devil. >>

So, does this mean I don’t have to kill humans now that I’m the Demon King . . ?

<< Because the number of monsters has been decreasing drastically, a Devil who will help them prosper is more important. >>

I was chosen for such a practical reason …  I don’t quite understand it, but it seems that all I can do now is fulfill my duties as the Demon King.

<< It is good that you are taking responsibility! Now, I will explain your abilities now that you are the Devil. >>

Oh, the Demon King gets abilities?

<< If I put it in terms of levels, will it be easier for you to understand? >>

[ Level 1 ]

lvl 1 「 Charisma 」

lvl 1 「 Demonic Growth 」

lvl 1 「 Demonic Submission 」

lvl 1 「 Fertility 」

lvl 1 「 Regeneration 」

lvl 1 「 System Guidance 」

<< These will become stronger as you level up; you will also gain new abilities. >>

As the Demon King, I have these abilities, huh … I wonder if the「Demonic Growth」ability will help increase the number of monsters.

<< That is correct! However, in order to use the「Demonic Growth」skill, you must first use the「Fertility」skill. >>

What does the「Fertility」skill do? Is it anything like Mendel’s Law . . ?(1)

<< lvl 1「Fertility」gives you the ability to control monsters by mating with them. >>

Wha- interspecies breeding!? Is this necessary to create monsters!? Really!?

<< lvl 1「Demonic Growth」is the ability to create any kind of monster by taking the semen of your partner into your body. >>

… … ?

<< As you level up, the number of eggs you can produce at once will also increase, so do your best to raise your level! >>

That … uh … ‘taking in my partner’ … I feel like something here is wrong.

<< Do you not understand? You mate with the monsters, as in ‘copulation,’ ‘sexual intercourse,’  or ‘fucking.’ >>

You don’t have to explain that so explicitly! Hey, what exactly are you talking about!?

<< When you take the semen of the monster you want to increase into your rectum, 「Demonic Growth」will activate and develop eggs of the desired species. >>

So blunt! I’m a man, you know!? Really!

<< That is obvious. >>

If you can only increase the number of monsters in such a way, you shouldn’t choose a man to become the Demon King! If you choose someone with a uterus, it would be a much more reasonable solution! Seriously!

<< Impossible. In the case of female monsters, the Devil must be able to impregnate them and ensure the survival of the species. >>

Well, if you put it that way, I suppose choosing a man makes more sense …

<< Unfortunately, there are very few female monsters remaining. It would be best if you mate with as many male monsters as you can. >>

Hey! I don’t want to do things like that with slimes and tentacles! It’s like something out of an eroge!

<< Regardless of their similarity to creatures from erotic games, slimes and tentacles are among the decreasing monster species, so please mate with them as soon as possible. >>

Why this …

<< I hope you are now suitably motivated! Do your best to rebuild the monster population! >>

The childish voice of the System resonating in my head was bright.

My life as the monster-making Demon King began like this.(2)