Believing She Has Been Reincarnated into a Baseball Game, My Little Sister Is Aiming for the Koshien, While I Give It My All to Keep Her from Finding out That It’s Actually an Ntr Game - Chapter 10

Today, on the bed where I usually sleep, I was shivering.

It seems my expectations were correct. This could indeed add a touch of reality to my goal of making it to Koshien.

“Maika, I’ve made a critical discovery… Come here right now.”

I called out to my only partner, Maika, to share this discovery.

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“What’s up, Kyugo? Did you find something useful online?”

Trying not to wake Riko in the next room, Maika sneaked into my room.

By the way, she ended up having to sleep in the living room with a futon. Riko wouldn’t allow anything else. Also, the T-shirt, shorts, and underwear she’s wearing now all belong to her and were supposedly left at this house. Riko found them and threw them at Maika with a disgusted look. A sleepover set is always prepared, just as you’d expect from a casual girlfriend. Of course, I’ve told Riko that we are in a “pure and clean relationship.”

“But Kyugo, I get that you’re anxious, but let’s rest for today. If you’re planning to go to Koshien, remember that your body is your capital. Oh, by the way, I found some creatine. I’ll prepare it, and you can start taking it tomorrow. Same amount as two years ago, right?”

“No, I think I need to take much more.”

“Really? Oh, you mean you want to load up because you haven’t taken it in two years—wait, does this room smell weird?”

Sniffing around, Maika murmured, “I kinda like this smell, actually.” Yeah, I should tell her before she says anything more unnecessary.

“Look at this. Take a look at this, Maika.”

I handed her an M-sized plastic bag that I had placed beside the bed. Maika took it with a puzzled look, untied the knot, and peeked inside.

“Huh? What’s this huge slime?”

“It’s semen.”

“Semen.”

“My semen.”

“Kyugo’s semen.”

“So much came out.”

“I produced so much.”

“As you can see, it’s unbelievably dense and viscous. It’s hard to believe it’s a liquid, right?”

“Die!!”

A roundhouse kick flew into my stomach. So much for the body being capital. And I had perfectly protected the contents of the bag from spilling a single drop. Typical Maika. And typical of my semen. It’s almost solid, so it doesn’t spill easily.

“What, did you get turned on by your passionately reunited sister and jerk off, you freak!”

“No… don’t get it wrong! I would never look at Riko, my precious sister, in a sexual way. That’s the worst thing I could possibly do!”

“And handing over a bag stuffed with your semen to your former stepsister isn’t included in the worst things?”

Well, I never intended to hand it over, okay? You just took it yourself, all right? I just wanted you to see it. My semen.

“Come on, calm down, Maika. Take a deep breath.”

“Take a deep breath while holding a bag of my brother’s semen in both hands?”

“Calm down and look at it. What do you think?”

“I think you’re insane.”

“It came out of my body, all in one go. You understand what this means, right? You must get it.”

“I don’t.”

Alright, let me explain.

“It means that my testosterone secretion is really high. It’s absolutely abnormal. I’m practically not human anymore.”

“…Huh!? So that’s what you mean…”

Maika’s eyes widened as she finally seemed to understand what I was trying to say.

“Basically, my body is probably really good at gaining muscle now. I’m on a whole different level compared to steroid users.”

The moment I resolved to go to Koshien in this world, I formed this hypothesis. Like other ero-game characters, the amount of semen I produced was extraordinary—something impossible in reality. As the “homewrecker” in an NTR game known for power, this attribute would boast an unmatched ejaculatory volume.

I couldn’t help but wonder if I had inherited this unique physique…

Originally, I was naturally skinny and struggled to gain weight from childhood. It was hard to gain both muscle and fat. Building this body took a lot of effort, with diet, training, and motivation management — something I could never have accomplished without Maika’s help. Still, I didn’t think I had caught up to the physiques of top national baseball players. Even at just under 180 cm, my height wasn’t much of an advantage. My physicality was always a concern.

But in this world, that concern might be resolved. No, more than that—

“From tomorrow, I’ll be overeating and going all out with weight training to make my body incredibly huge. This will be the biggest factor in us making it to Koshien.”

This was the conclusion I reached after playing high school baseball for two and a half years in my first life: to get to Koshien from a weak school with no promising players, I had no choice but to develop physically and overpower others. However, with less than four months until summer, it was impossible to bulk up significantly under normal circumstances.

But now, I’ve acquired a cheat ability far surpassing any doping. All that’s left is to eat, sleep, and train. I might truly become a monster.

“Kyugo, I didn’t know you were thinking about all that,” Maika said, mixing a shade of worry into her astonishment.

“But, is that really okay? If it’s going to strain your body, then absolutely not, okay?”

“It should be fine. My body is natural, after all. This testosterone level is a trait I was born with. It’s different from people who have been artificially given anabolic steroids.”

Of course, even though it’s natural, this abnormal testosterone level might cause some long-term health issues. But there’s no point in letting Maika know that and causing unnecessary worry—the benefits far outweigh the drawbacks.

Probably, the original Yamada Kyugo wasn’t working out at all. He was a delinquent, after all.

Yet, he had a physique similar to mine, which I had achieved through relentless effort. He just casually played baseball and fought, living life on a whim. Truly, it could be considered a natural gift.

“Honestly, I wasn’t sure until I actually ejaculated. Since my face and body have become mine, it was possible that even my hormonal balance could have changed from the original Yamada Kyugo’s. However, after testing, I found out it had been inherited.”

Still, I was confident.

This indescribable exhilaration bubbling up from within me—well, it’s a strong sexual drive—but this impulse wasn’t something I had before my reincarnation. In the previous world, my libido and vitality were just average.

Perhaps, since this is a game without NTR, the world wouldn’t allow this ability to be lost.

An average ejaculatory volume for the homewrecker in an NTR game could shake the very foundations of this world.

My semen being scarce might well be the end of this world. Okay, maybe that’s an exaggeration.

“So, about the hormonal balance… Maybe even my menstrual cycle has changed from my previous life?”

“It should be about time, normally.”

“Right. So, about preparations—wait, why do you know your sister’s menstrual cycle?! Die!”

She kicked me and stormed out, fuming.

Well, we’ve lived together for years, and naturally… It’s helpful to share that kind of information, isn’t it?

Alright, I’ll buy some of Maika’s favorite sanitary napkins to cheer her up. I wonder if they have the same brands here—Sofy’s ultra-thin, light, organic cotton pads for light days without wings, and the ones for heavier days with wings.

“Good grief, such a troublesome former sister. I wish she would take a leaf out of Riko’s book.”

But when it comes to supporting my condition, Maika is top-notch. She’s right; I should go to sleep soon, for today.

Sigh…

Thus, our new life in a new world finally came to a close on its first day—

“Ah! Maika took my semen back with her!? What does she plan to do with it!?”