Mio is in her tenth term.

The rest of the party is in their ninth.

So...

Age gap!

(City Public Bath)

(A day after they reached the City)

Sena,

Was Floating.

Yaaaay….

No no, be serious, Sena was gently floating around the big, warm bath, her usually-tied hair fully freed. Without any words, she just gently floated around, gazing mindlessly at the celling.

Until…Eunie decided to enter the bath.

"Hey, Sena, love, whatcha doing? Something on your mind? It's pretty rare to see you this quiet." Said Eunie, as she put her foot in the bath. As the taller girl entered, she made some waves, disturbing Sena's gentle float spree.

"Huh? What do you mean Eu… Gah!" Sena gasped, as she got submerged in the warm water as Eunie's wave hit her.

"Hehe, look at you, sinking like a pile of rocks." Eunie giggled, now relaxing in the warm bath. Mio soon joined the party.

"Yeah, Sena, something wrong? You're usually pretty talkative when we bathe." Said Mio, sitting next to Eunie.

"Mio-chan…" Sena groaned as she rose over the surface.

"Come on, spill! There are no boys in here, so let's use it to our advantage! Man, I still can't get used to this split-bath thing…." Eunie said, splashing water on Sena.

"Okay, okay, Eunie! Stop splashing!"

"Nope!"

"Eunie…" After Eunie splashed enough water that Sena looked like a drenched mouse, she finally stopped.

"So, Sena, what were you thinking while you were acting like a boat there?" Mio asked.

"Oh, yeah… Uh…it was about the things we learned today… The lesson in the morning…?" Sena opened her mouth.

"Aha… The doctor's lesson? About…uh…yeah…sex? Or babies? Bodies?" Asked Eunie, gesturing the various things that the doctor told them.

"I can't say that I didn't think of that too… Since the lesson was indeed shocking and the doctor told us many things we never knew…" Sena said, scratching her drenched hair.

"Yeah, it was certainly…something…" Mio added.

"But that was not the main thing in my head. It was… Monica's short lesson after that…"

"Monica's…? Oh, yeah, the lesson about culture? That was pretty mind-blowing, too!" Eunie chirped.

"So…which from the lesson was you focused on, Sena? There were many things there..." Said Mio.

"Uh…yeah… Mmm… Mio-chan, do you remember the lesson about siblings?"

"Siblings…? Yeah…I think I do… Wasn't that the term indicating multiple people born from the same couple?" Mio said, tilting her head.

"Yeah…."

"So… Why were you so focused on that, love?" Eunie asked.

"You know… After learning about the true human nature and babies… I was just so mesmerized at the fact that a human can create a new life with another human… And it blew my mind that I was also able to that if I had…sex…with…another person… But…I never thought about having more than two babies! Isn't it…crazy!? Like…how is that possible? You…have another person next to you…who is born from the same source as you! Sharing many same traits with you…and you take care of each other…! How would it feel…?" Sena said, as she covered her mouth in awe. Her head was just filled with thoughts.

"Oho… I never expected you were thinking that much about the term…" Said Eunie.

"Hehe, that's so you, Sena." Mio giggled.

"And…another thing. About the names…? What should I call this….? Anyway, the names you call your siblings. I thought…it was…pretty cool…! It's like you have another name for your siblings…! You call an older male sibling onii-chan or onii-san(Big Brother), an older female sibling onee-chan or onee-san(Big Sister). And you call your younger male sibling otouto(Little Brother), and a younger female sibling imouto(Little Sister)…! Isn't it so cool?" Sena started to float up and down.

"Hmm… You know, hearing from you, it seems pretty cool! We never thought of calling other people without by their names… We just call everybody by their names without thinking about their ages…gender… Or anything. Heh, pretty cool, I say." Eunie chuckled.

"…." Mio stayed silent, hand firmly crossed in front of her chest.

"Mio-chan…?"

"Heh…hehe…."

"Mio-chan…..?"

"Hahahaha! Oh, Sena… You're so precious…." Mio laughed, wiping the tears from her eyes.

"Mio…chan…?"

"You know… Come to think of it… Haha… What term were you guys on?"

"Hey, you forgot? Nine!" Said Eunie.

"Yeah, nine. And I'm ten… So…"

"So….?"

"Doesn't it make you guys my… imoutos…?" Mio said, slightly blushing.

"Wait, Mio, you serious…? We're…not even from the same country, remember…?" The only Kevesi girl said.

"Well, yeah, but we're not in a regular relationship, aren't we?"

"Uh-huh!" Sena nodded, her eyes sparkling with enthusiasm.

"So…what do you want to say, Mio?" Eunie said, laying back.

"Uh…hehe… You know, Eunie… Like Sena said… I was…also pretty interested in that sibling stuff…In fact… I thought about… Sena…when I first heard about the term… I met her when I was in my third term and I was never separated from her since that… We weren't really born from the same womb… But…we did believe that we were born from the same Queen, didn't we?"

"Yeah!" Sena nodded.

"Hmmm… I think I know your conclusion…" Eunie mumbled.

"Oh? Then guess it, Eunie. What will I say next?" Mio said, putting her face closer to Eunie.

"Uh…so… You want us to be your imoutos, do you?" Eunie said, with a smirk.

"Ah…haha…" Mio blushed.

"So, am I right?"

"…..Yeah…." Mio admitted.

"Really!? Mio-chan?" Sena stood up.

"Hehe…. You can forget what I said…" Mio scratched her head.

"No! No! Never will! I…I always thought Mio-chan as my mentor, friend, and my role model! If…Mio-chan wants to be connected closer… I would love to!" Sena said with passion.

"…Really, Sena…?" Eunie tilted her head. But her voice didn't reach the heated-up sisters.

"Sena….!" Mio covered her mouth in excitement.

"Then, Mio-chan…"

"What is it, Sena?"

"Can I call you… Onee-chan….from now…?" Sena muttered with a blush.

"Totally! I would be honored if you call me that!" Mio said, spreading her arms.

"Yippee! Thank you, Onee-chan!" Sena exclaimed, getting into Mio's arms. Mio held the little sister tightly as she came close to her.

"Whoa, you guys really doing that?" Eunie gasped.

"….Eunie?" Sena said, staring at Eunie.

"…..Huh…?"

"How about you try it this time?"

"Wait, me too? But I'm…"

"Not from the same colony with Onee-chan?" Sena said.

"Um…yeah! And…I...met you guys like only two months ago! I…think I'm not ready ye…"

"Eunie,"

"Y…eah…?"

"Do you like Onee-chan?"

"….Eh?"

"Come on, Eunie, do you like her?"

"…Ugh…I…can't say I don't….?"

"Then, why not? Onee-chan did say that we were in a special relationship, too! Besides Ouroboros, we came through a lot of hardships together, and we overcame all of them. So, Eunie..."

"….Yeah…?"

"Do you still think we're strangers? Come on, Eunie, it's a great opportunity to get even closer…!" Sena said, her eyes were now burning.

"….." Eunie dropped her head.

"You don't need to if you're uncomfortable, Eunie. I don't want to…"

"Heh, don't worry," Eunie snorted, as she slowly lifted her head.

"Eunie….?"

"Do you still have some space left in your arms? Mio nee-chan?" Eunie said, with a Eunie-ish grin on her face.

"Eunie…!"

"Of course I do, my cute imouto. My arms are always open for my sisters." Mio said, opening her arms even wider.

"Then I won't hesitate!" Eunie exclaimed as she jumped in to join Sena.

Like that, the three girls soon joined in a big embrace.

It was the slightest change.

Mio-chan to Onee-chan.

Mio to Mio nee-chan.

But it felt so different.

An unknown sensation of warmth spread out from their chests, and they soon filled their entire bodies.

They weren't their interlink partners, but they felt a similar feeling.

They felt connection.

They felt affinity.

So this was what the City dwellers called…

Family.

Now they felt that they were starting to understand humanity, little by little.

(Omake)

"Huah….!" Lanz groaned, stretching his limbs out to be prepared for the morning workout.

"Had a good sleep, Lanz?" Noah asked, approaching him.

"Yeah, the bed… Holy sparks… The bed! Noah, can you believe it? The bed! The sparking…."

"Alright, I get it, Lanz. Yeah, long time no bed, eh?" Noah chuckled.

"Totally, even better than the colony bed," Lanz added.

"Huaaahhh…" Eunie yawned, slowly walking toward the boys.

"Morning, Eunie!" Lanz gave her a powerful smile.

"'Sup! Looks like you had a decent sleep there, big guy." Eunie giggled.

"'Course, I'm in my best condition now! Hey, by the way… Where's Sena? She usually comes out early for the morning workout…" Lanz asked.

"Oh, Sena? She's probably…with… Mio nee-chan right now. Taion would be there, too."

"I see…. Wait, Mio nee-chan? What was…."

"Eunie! Morning!" Sena chirped, walking with Mio. Taion followed them from behind.

"Morning, Sena. And morning, nee-chan." Eunie gave some strength to certain words.

"Morning, Eunie." Mio smiled at her.

"Okay, now that I met Eunie… What is up with you guys now?" Taion blurted out.

"Huh?"

"About this whole Onee-chan, or… Nee-chan… Since when did you call Mio that? I thought only Sena was calling her that, but Eunie too?" Taion scratched his fluffs.

"Oh, that. We…decided that when we were bathing yesterday. We're now sisters." Sena giggled.

"Yup. Hey, Taion, wanna join?" Eunie smirked, elbowing him.

"Huh….?"

"Come on, we need a brother here!"

"What are you…"

"Hey, Lanz! How about you? Wanna do this with us?" Sena said, as she clung to Lanz.

"Me….? Well…uh…"

"Believe me, it's gonna feel different."

"Really….?"

"Uh-huh!" Sena nodded powerfully. Like that, the two girls started to talk with their interlink partners about the conversations from yesterday, and the suggestion to join the small family. Which…had Mio as the headmaster.

And Mio, the big sister herself.

Was walking towards her own partner.

"Hey….! Good…morning!" Mio gave Noah an awkward smile.

"….." Noah stood there, keeping his silence.

"Uh…hey….?" Mio scratched her head. Noah seemed to be thinking about something.

"Hmmm….." A small grin appeared on Noah's face.

"Heh," Now he was slightly laughing.

"Morning, Onee-chan." Noah said, with a gentle tone.

"Huh? Noah?" Lanz gasped.

"Wait, without hesitation? Damn, Noah, my man!" Eunie laughed, giving Noah a five.

"Uh…what was…." Mio mumbled, now frozen in place.

"Well, no particular reason. I thought…following Eunie and Sena's plan…would be…great. That's all." Noah chuckled.

"Oooh…..?" Mio gasped.

"And…you know… I was always conscious about you being a year older than me… And…the lesson from yesterday did have an impact on…" Noah continued his explanation, but…

It soon got interrupted by a finger.

"…..Mio….?"

"Thank you, but… You know… There…are…some things in this world… That…is better when it's not explained with words." Mio said, her face a bit scarlet.

"Oh…yeah, right…. I was being…too long, right?"

"Well… Hah… I just don't know at this moment… Just…do me a favor, will you?"

"Yeah?"

"Call me Onee-chan again."

"Uh…okay….?"

"Onee….Chan…?"

"Mmmm….!" Mio slightly jumped up and down, her ears perking up like crazy at the statement.

"You…you alright…?"

"…Please, one more time."

"Uh…again…? If you wish…?"

"Onee…chan…?"

"Mmmmm….!" Mio's ears were now skyrocketing.

"Hey…isn't Mio-nee being too high right now…?" Eunie whispered.

"Let's just let… Onee-chan have the time of her life..." Sena replied.

"….Yeah…"

I wrote this based on the Japanese version since I prefer the family terms in Japanese rather than English since they're similar to the terms in my culture.

Oh, yeah and one disclaimer.

Not all siblings are like th...