Isekai Wisdom Chapter 03 Deflowering my own Sister


03 Deflowering my Sister

「You don’t have a peepee?」


Is it possible to shock to find that something wasn’t there?

Caliber, my idiot brother, was so arrogant and stupid that his very existence was a nuisance.


When I undressed this brother of mine, I found nothing in the place that had to have something.

Meaning, his dick.


Instead, what I found is a smooth area that’s still too young to grow hair.


That’s not something a man should have.

Even if it shrank to the size of a pea due to shock and fear of encountering a monster, it should still have something


There’s only one conclusion to that.


I thought that he’s an idiot brother, but it’s an idiot sister?


「Wait, Caliber’s a girl?」


No, that can’t be.

What’s impossible you ask? I’m this person’s brother. I lived together with her, albeit reluctantly for as long as I could remember.

Under the same roof.


You can’t possibly mistake the gender of the person in that situation, right?1


「Wrong! I’m a man!!」


The person herself is saying that too.


「No, you’re a woman! That thing in your crotch is a vagina!!」


The young fruit that’s yet to reach full maturity.

The smell of ammonia which had been unpleasant earlier has become rather sweet.


「I mean, women can’t become knights!」

「Huh, what do you mean?」

「That’s what they told me so I had to become a man to become a knight!」



Let’s sort out what Caliber said.


Caliber’s vocation is “Knight”

Knights are common in the city. If you do well, you can get ahead and be promised a rich life, which is something to envy.


And so, the person herself who holds the knight class inspired the unthinkable because she’s envied?

She’s been so arrogant that everyone frowns on her.


I don’t know if women can become knights in this world or not.

It’s a medieval era, but it’s a fantasy world.


Still, I hope that the “Kukuro”2 female knights take root in this world as well.




Then, there’s the beginning of a female knight in front of me.

This idiot brother, I mean, idiot sister Caliber.


「You see, men need to have a penis in them」

「Huh? What?」


Caliber who doesn’t know about penises is so cute.


「It’s this」


I pulled my pants down and ripped out my little beast that’s hiding inside.

My penis was erect, and as soon as I released it, it bends as if it wants to shoot the sky.


I wonder?


「Hii! What’s that?」


Caliber’s witnessing an erect penis for the first time in her life.

I can see the fear on her face.


「Why? Why is there a stick-like thing growing out of your pee area? That’s just a hindrance, isn’t it?」

「Hmm, well, it changes to a form that won’t get in the way when you don’t need it」


It’s one of the mysteries of life.


「Men have a penis, and women don’t. Well, this is the most noticeable difference between men and women」

「Then, if I have a penis then I will become a man too? Tell me how to grow one?」


Hmmm, seems like the biggest unreasonable request I had in my life since reincarnation.

Putting that aside.


「Try saying “penis” again」

「Hm? Penis?」


「Penis, penis, penis, penis, penis?」



Having a young ignorant girl talk dirty is nice.




I look around my surroundings.

We’re in the forest that’s told who knows when danger comes. The demon bear which looked like it owned the place was so badly beaten that it’s unlikely to come back.


It’s outdoors, and the deep forest is a closed room with no walls, completely free from the gazes of the public.

Nobody other than the two of us is here.


「In the meantime, let’s hang your pee-soaked clothes on a branch and they’ll dry eventually. Let’s dry our coats just in case too」

「Huh? But our upper clothes aren’t wet, right?」

「Just do it」


I made my confused sister raise her hand and I stripped her upper clothes too.

Caliber who had not only her lower half but her upper half taken off is now completely naked?


「Hey, why are you stripping too? You’re not wet, aren’t you?」

「Don’t mind it」


I took off my clothes too and the two of us are now in our birthday suits.


I held Caliber’s legs as she’s still unable to stand, spread them to the side, and rub my erect penis against her legs.


「Eh? Eh? What are you doing? Eh?」


I rub my glans on her beautiful slit.

It slides from the moisture of her pee so it feels good.


「Do you know why men and women are this different?」

「I don’t know! I don’t care! I’m going to be an adult man」

「If you know the reason, you’ll be fine being a woman」


Nuchu, nuchu, nuchu, nuchu.

The act of rubbing my penis against the muscles between her legs is already sensual and pleasing.


「Hm? Yuhaa! Ahn?!」


Seems to be the stimulation is sent from between my legs.

Caliber also squirms and is puzzled over the sensations of a woman she’s been rejecting.


Slimy moisture grows from her crotch. A different liquid from urine is leaking out of this woman.


「What’s going on? Somehow, it feels itching down there」

「That’s what it means to be a woman. It’s a pleasure only for women you know」


Men have their pleasures too though.


Well then, Caliber who’s surely a virgin, and refuses to be a woman, won’t have any sexual pleasure developed yet.


Still, the reason why she’s opening up so easily must be because of me.


My vocation, rod master’s skills, is making a woman blossom immediately and irresistibly even if it’s not yet ready to accept it all.


Skilled hand, God Hand, Pleasure Critical Rate Increase (Greater) and Pheromone (Strong)


This is where even the most stone-cold insensitive woman can develop her sexual pleasures and become wet.

I touched her breast with both hands while rubbing her slit with my penis.




I fondled her still-undeveloped plane of tits but only the protruding parts are already womanly, her nipples are as big as peas.

Men can’t imitate such large nipples.


I use my fingertips to pike it and Caliber twitches as if she’s been electrified.


「Nhiiiii?! Hiiii!! Hyiiiiiii!!!!」


Pleasure Critical Rate Increase (Greater) has been activated.

Caliber, who refuses to be a woman, has her body melting from my mouth and hands.


I think this is good enough.


「I think it’s about time for the main thing」

「Huh? There’s more? Stop, I’m at my limit. If you go further than this I feel like I’m going to fly, I’m going to go somewhere!! Nooooo!!」


My rod master power has loosened up the hole that shouldn’t have been ready yet.



「Ohooooooooooooooo?! Ooooh! Oooooooooooh?!」


I guess this is the birth of Caliber-neesan as a woman.

Congrats on your early graduation on your virginity.

I never thought that the person I’d give my virginity to would be my blood sister.


Well then, let’s start moving.

Pa, pa, pa, pa, pa!


「Ooh, oooh?! ooooooh?! What’s this? Your penis, your penis is stuck on my crotch!?! You’re piercing me, I’m going to die!!」

「It’s okay, you’re not going to die」


She doesn’t know what’s going on with her body.

Well, I’m sure my sister would want to cry too but I can calm her down.


「All women can do this. You have an organ in your body that can take in the penis. Nee-san’s body is just doing what it’s supposed to do」

「Why does it have to swallow in a penis?」

「Well, that’s for pleasure, I guess?」


I’m sure that there are other things to explain but I’ll skip that and focus on pleasure for now.

This is the first time I’ll have sex in this other world.




I should increase the angle of the piston movement too.


「Nfuu?! Fuu, oooooh!!?」

「How is it, does it feel good Nee-san?」

「I don’t know, but it’s making me feel itchy ♥♥」


I’m going to stick to calling her Nee-san now that her gender has been identified.

It fires me up to bang her while calling her my sister.


「Nee-san’s pussy is making my cock feel good! Let’s have sex every day from now on」

「ehaaaaaa!♥♥  Hyaaaaaaa!!♥♥」


If we do that, Nee-san will also understand how lucky it is for her to be born a woman.


「Noooooo!! ♥♥ My body’s floating! ♥♥ I never knew about this. I’m flying! I’m flying! I’m flying!!! ♥♥♥♥」

「Haaaaaaa! Here I go!!!」


This is my first-time sex in another world so naturally, it’s got to be creampie.


Byururu, byuuuuuuu!!!




Nee-san’s whole body trembled and twitched as soon as she received my semen in her womb.

Her petite body shimmers in the bewitching glow of a woman.


「Hiii ♥♥ Hiiiiiiiiiiiiiii ♥♥」

「See? It’s okay to be a woman, right?」


You can’t change your gender no matter how much you want to.

So, I’ll have sex with her all day long to teach her the happiness of a woman.


For me, there’s nothing better than having someone who I’ve always thought of as a nuisance living with me as my ideal sex partner.


「Nee-san, let’s kiss. Kiss」

「Huh? muchu, chuu ♥♥」


I’m doing whatever I want with the exhausted body of a young girl who just climaxed for the first time in her life.

From now on, I’m going to soak my sister in sex and turn her into the erotic woman I want her to be.


Nee-san will no longer talk nonsense that she wants to be a man, and my penis will be satisfied. Two birds in one stone.


For now, I went inside Nee-san’s pussy one more time. Her body’s become sensitive bounced and she moans “Hmm ♥♥ Hmmmmmmm♥♥♥♥”


「Aah, Nee-san’s pussy feels great. Let’s have sex every day. Definitely」

「Hyaaaaaaa♥♥ Ahn ♥♥ Nooooooo ♥♥ The wave of pleasure is coming again!!!♥♥♥♥」


Exploring the forest with my brother had been nothing but a nuisance and a waste of time, but now, it’s going to turn into a blissful time on the day.


This is how my otherworld reincarnation life became smooth sailing.




Five years passed.



  1. Oh that’s where harem shows prove you wrong
  2. Kuh, Kurose or “Kuh, Kill me”