What do you mean my cute disciples are Yanderes?

(MC POV)

I looked at Elaria who was standing in front of me with sparkles in her eyes, clearly looking forward to the date we were going to have.

"I take it you're next?" I asked.

"That's right, Onii-sama!! I'm here for my lovey dovey date with my Onii-sama!!! Ehehe~ How bold Onii-sama, for making me say that out loud~"

No, no… You said it yourself without any prompting from me…

She then placed her hands on her hips with her feet shoulder width apart to give me a look of anticipation, "Alright! I'm ready, Onii-sama! Where are we going?!"

I raised an eyebrow at her, "I thought for sure you had a destination in mind with how ready you appear to be."

"Oh, I'm ready for my date with Onii-sama of course! Anywhere is fine as long as I have Onii-sama with me!"

I chuckled, "As nice as that is, I would still need you to let me know what kind of date you want to go to so I can create the World for us."

"Ehhhh… I'm fine with just hanging out with Onii-sama though. I kind of miss those days where we would do nothing and Onii-sama would talk to me about all the interesting animes and mangas back in your past life."

…

At least she's pronouncing those terms correctly now since she has experienced living in the other World for a time.

"Hmm… Then would you like to just go back to our hometown and pass the time doing that?"

Her confident posture crumbled almost immediately when she heard my suggestion and she quickly shook her head, "Eh?! No, no, no… That… That's really boring right?! Let's not go back, Onii-sama! After all, that… Ummm… We should go somewhere new! Yeah! Let's just visit one of those Worlds that are similar to the stories you told me before! It's way better to experience it for ourselves than to just talk about it, right?!"

…

Ok? Why does it look like she's really desperate to not let me go back? Did something happen back 9in our hometown or something? I'm almost too scared to find out.

Perhaps I should stop by to check it out after all?

As though reading my mind, Elaria stepped closer to me until her body was pressed up against mine while her arms wrapped themselves around my waist.

"You don't need to worry, Onii-sama! Everything's fine! There's absolutely no reason for you to go and see what happened to our hometown! It's just as you remembered it so there's no point seeing it again!"

…

Definitely suspicious but now I'm convinced something definitely happened to it, although now I figured it would be better for my mental health to refrain from finding out what exactly happened to it.

I sighed, "Alright… Let's see what kind of World you want… We have talked about quite a lot of different stories so in some Worlds you get inspired by the plot and end up making them into reality. I just need to know what kind you're in the mood for right now."

"Can I pick anything?"

I nodded.

She continued to hug me while she considered for a moment.

"How about… Oh, I know!! A World where we are galactic conquerors!! We'll have big warships and our empire spans across the entire galaxy!!"

…

Funnily enough, there were several alternate universes where this exact thing happened with some of them happening even without my direct involvement.

One thing that was consistent with all of these universes was the fact that she was a galactic dictator in all of them.

Oh well, that's no big deal. I just need to find an interesting one where I was directly involved in her warmongering in some way.

Since Elaria's date required me to create more than just a single World, I went ahead to create another dimension within that same space so that I could stuff a galaxy in there for us to play around with.

What? It's just creating a galaxy, no big deal, I've already created universes before so this is practically easier than that.

Oops, better note down the interesting stuff in that so that I can think about making my own World later as well.

Nodding at my little sister to let her know I picked a place for us to go to, she hugged me even tighter while shooting me a toothy grin to let me know that she was ready as well.

Concentrating on the new galaxy I made, I sent the two of us over in the blink of an eye, taking over the positions of the us in that universe.

I woke up in an unfamiliar bed alone.

It was obvious that this bed wasn't meant only for me with the fact that the other side of the bed had its blankets tossed aside and the pillows were also left in a haphazard pile like someone had just tossed them aside while getting up.

There were ropes tied to the bed's headboard, discarded candles and even a paddle and handcuffs discarded on the bedroom floor.

Ignoring those, I got out of my own side of the bed and only managed to start putting on my clothes when the door to the room suddenly slid open to reveal Elaria standing there in full military uniform that was similar to a navy captain's design.

"Onii-samaaaaa!! This is so cool!! I… Eh? Unngghh… This is weird… I'm supposed to be going to the bridge and… Why… Ah?"

I went up and patted her on the head, "Slow down. Separate your original memories and the memories of this version of you. Then slowly integrate them while maintaining the separation, it'll be better that way."

"Ehehe… Did the others experience this as well?"

"Well… Tsuki and Manami didn't since they have experience with this memory thing before so they adapted to it pretty quickly…"

"What?! No way is that stupid girl better than me!! I'll show her!! Gnnnnnggghhh!! There! I'm done! Wahahaha! Let's go conquer that puny little civilisation that dared to insult you, Onii-sama!! Oh~ You're looking really nice topless like that! Do you think you can just go with me like this? Aha… Ahahahaha!! I want to destroy their stupid planet so bad!!"

…

Did she just combine the memories of both World's versions of her into one and create a new self?

That's not good… I better just sit her down and help her through this before we go any further…

That's going to be a really big problem, you know? Especially when you use two versions of you who are really, really different…

No, really… I mean it… So stop pulling me for a moment, Elaria…