Part 1
A busy daily life. Although it was mostly the same, Stella couldn't call it boring.
Especially because of Rudy nii-chan.
There was a lot that Stella didn't understand or know. Like how Rudy nii-chan kept making a bottle of baby formula out of thin air or where he kept getting those baby diapers when the world seemed to be a complete fantasy setting.
But as the days went by, she was more sure in her evaluation of Rudy nii-chan.
He was a cheat.
One day, Rudy nii-chan took Stella out of the house. And when he did, she found out that what she thought was a 'house' was actually a giant black tower that looked exactly like where the final boss would wait.
But that wasn't the important part. Instead, it was the conversation he had with Rika when he took her out.
"*Babies need fresh air, right, Rika?*"
"*Of course! Though Rika thinks that the Magic Continent might be too harsh for a Human infant.*"
"*But not here, right? Since it seems like we captured a microclimate of some sort?*"
"*Rika is unaware of 'microclimates', but Rika agrees that this area is safe. Maybe since the space was transported from the Human continents?*"
"*Hm...*"
A seemingly ordinary conversation.
From it, Stella learned that they were in a place called the Magic Continent and that they were lucky enough to be in a hospitable region.
So she thought it would end there. Since her Onii-chan was protective, she thought that he would just return inside and spend time keeping her safe until she grew up enough.
But instead...
"*It'll be a bit hard to control the weather patterns, but temperature and water should be doable. As for the terrain and fertility... The ambient mana is a bit intense, but if I convert that...*"
Stella had been facing forward at the time. Because of that, she could see it.
Scattered pieces of geography. A lush grassland suddenly cutting off and replaced by a cracked and dried wasteland. A clump of trees that looked plucked from a forest. A pond in the middle of that dried wasteland, already half evaporated. And then the peak of a mountain jutting out from the ground.
For the first time, she saw the aftermath of the incident that sent her and Rudy nii-chan to this foreign land.
And immediately after that-
"*You! Rudy! Do not lie to This One! You are a demon in disguise- No, the reincarnation of Laplace, are you not?! S-Such a feat...!*"
Rika's panicked and terrified voice.
"*I'm perfectly human. And anyone can do this, you know? All you have to do is create an artificial leyline and connect it to elemental mana streams already present in the area. Then you just direct it according to what you want and lock it in place with a few magic formations.*"
Rudy nii-chan gave a nonchalant response that sounded rational.
Yes. 'Sounded' rational. But the reality...
Stella stared at the utopian landscape that popped into existence in front of her eyes while Rudy was talking.
Shimmering clouds that floated from the mountain peak, blocking out the harsh sun.
Lush green grass and a cobblestone pathway to the pond, lined with colorful flowers.
The forest, suddenly expanded with ethereal trees that had golden branches and fluffy white leaves.
And the wasteland that had separated all the disparate bits of geography, completely gone and replaced with lush greenery.
Not only that, but there was a constant gentle breeze blowing. Even the harsh sunlight had turned into a faint warmth.
Stella turned to look at her Onii-chan.
He noticed and stared back.
"Chi."
'You're a cheat.'
Rudy laughed and then poked Stella's cheek. "Don't worry. Like I said, Onii-chan will keep you safe. See? Now we can go walk around outside instead of staying cooped up in the tower all day."
That was nice. And it was good that Rudy nii-chan was considering that. But...
Don't you think terraforming just to take a walk with your baby sister is overkill, Onii-chan...?
-SNG-
Part 2
After deciding that he wasn't going to let Mother Nature get in the way of letting Stella enjoy it, Rudy mostly took Stella outside to play.
Random fairytales and plagiarized Anime storylines treated as fairytales. The occasional language lesson with him creating props to teach her the words.
And rants.
Lots of rants.
Rants about how adventurers were stupid muscle-brains who kept wanting to test themselves against Ruijerd and Roland.
Rants about how annoyed he was at the procedures of rising through the ranks as an adventurer.
Rants about how he wished he had learned the Magic Race language earlier so he didn't have to rely on Rika translating it bit by bit and getting bored.
And more rants about how everyone on the entire continent seemed to be so poor that even a casual flash of some gemstones were enough to get them to risk their necks to dungeon dive and look for humans they didn't care about.
Yes. Rudy nii-chan had a lot to rant about.
Enough that Stella wondered if her Onii-chan's hair had always been white, or if it had turned that way from stress.
...Considering how easily Rudy nii-chan ranted, she was starting to think it was stress.
But anyway, Rudy played with Stella a lot.
Carrying her around on walks. Laying her on a blanket atop the grass to look at the blue-green sky and the sun that was always conveniently blocked by a cloud. Telling stories...
Everything a big brother would normally do with their baby sister.
Which included protecting her from dangerous animals... Or in this world, monsters.
It happened one day after Rika was sick. Mister Ruijerd was home keeping an eye on Rika while Mister Roland was out organizing a group of people to start constructing some houses in the distance.
That day, Rudy nii-chan was carrying Stella as always while he kept an eye on the construction from a distance.
"...It's a bit unexpected, but it looks like Onii-chan's going to be a Guild Leader soon, Stella."
"Ba."
"Yep. It's pretty bad." Rudy sighed. "Seriously. I keep telling everyone I'm a kid, but they say that it has to be a lie. Even those hardcore Milis followers we rescued think I'm the reincarnation of Saint Milis or something instead of a normal kid."
'Onii-chan. When you can make food out of thin air and reshape the land, I think even a hardcore non-believer will start reconsidering their beliefs...'
Rudy sighed again and then leaned back in his chair, holding Stella up to watch the construction.
And then something happened.
"*Watch out! It's another distortion!*"
"*Astolfo! Keep the rookies safe!*"
"*Kay~! Whatever you say, Captain Rolo!*"
Loud chatter. The sound of steel being drawn. Crackling lightning and ominous sci-fi sounds like lasers or engines being revved up.
And then terrifying roars cut through the air. Similar to the ones when Stella had been born.
She wanted to watch, but her body had a visceral reaction and started crying on its own. Not just crying, but bawling her eyes out.
'Stupid baby body! Calm down!'
Of course, no matter how much Stella told herself that, it didn't work.
The earthshaking roars and thunderous footsteps coming towards her made her baby body shake in fear.
But only for a few seconds. And the reason for that...
"Shut up! You're scaring Stella!"
A boy's voice, calling out in a petulant tone.
And then Stella saw it.
The scene was a bit blurred because of her tears, but she clearly witnessed what happened next.
The monsters were dragons. At least, things that looked like dragons. Giant, scaly reptiles with glimmering green scales and leathery wings.
Scary.
Seeing them rush forward reminded Stella of that famous American dinosaur movie.
But before those monsters took two steps, they were struck by lightning.
Crimson bolts straight out of the blue, stunning them in place. And after that, the ground opened up like a giant mouth and swallowed them whole before slamming shut with a loud *crunch.*
And then it was quiet, the terrain back to normal like nothing had happened.
Silence.
But before long...
"*Yatta~! Boss defeated the Grimoire Dragons!*"
"*All hail Lord Rudras!*"
"*Long live Lord Rudras!*"
Rudy let out a deep sigh and wiped away Stella's tears. After that, he looked at her and said, "See, Stella? These guys are crazy."
Stella sniffed and then let out a smile.
Seeing that, Rudy smiled back and patted her head.
But on the inside, Stella was thinking...
'Onii-chan. I think you're the crazy one here...'
-SNG-
Part 3
The days continued to pass. As they did, Stella was slowly starting to agree with the people that said Rudy nii-chan wasn't human.
It took a bit since Stella wasn't conscious for most of the day. But as time passed and Stella could stay awake longer and longer, she started to realize something very important.
Rudy nii-chan didn't sleep. He didn't eat either. Or use the bathroom.
She first noticed a few months in when she woke up with a nightmare.
It was dark, and in the middle of the night, she had a dream about that day.
How Dad said he would be coming home early. How Mom said they would be having salted salmon and how Stella... 'Shizuka' had complained about eating something so boring.
Right.
She had taken it all for granted.
Then she remembered having the fight with Aki. Complaining about how he was getting too close to that one girl. Watching him storm off, and then...
"Shh. Onii-chan's here."
Warm hands holding her close and gently rocking her.
"I know, I know. It's scary, isn't it? But it's okay."
Stella sniffed and then nuzzled close to Rudy's chest.
A familiar lullaby. A song about a great big dango family.
Singing that to her in his childish voice, Rudy held her close until she fell back asleep.
...And then from that point on, he made sure to hold her throughout the night.
Which was how she noticed it.
There were a few times after that where she had nightmares, but Rudy nii-chan was there every time. Not only that, but he wasn't tired or drained. Instead, he was always working.
Flipping through reports, sketching out intricate magic formation designs, having hushed conversations with Roland or Mister Ruijerd about adventurers...
At first, Stella thought he was just pushing himself. That he was being super responsible and forcing himself awake for her sake.
But then she realized that wasn't the case. And the reason for that...
"Hm... So constantly circulating healing mana like I used to keeps homeostasis like I thought. And there don't seem to be any side-effects... In the worst case scenario though, I'll need to forcibly reset things with a God-Ranked healing spell... which I don't have. Fortunately, the Clairvoyance Demon Eye works both directions and I can memorize the underlying molecular structure enough to fudge a restoration with healing magic... But is it reducing telomeres by constant regeneration? Wait, can I stop aging by restoring the telomeres directly? No, is that how Rika's revival works? Saving the snapshot in mana and reversing the process?"
A long mumbling rant about something that sounded a lot like research into practical immortality.
No. Onii-chan wasn't forcing himself to stay awake. He was already staying through the night doing research on topics that were completely like what a Demon Lord would look into.
...If this is what her big brother was like, what was the rest of her family like, Stella wondered...
-SNG-
Part 4
Stella could finally sit up by herself. At last, a bit of independence!
For a while, she was worried that Rudy nii-chan was going to keep holding onto her forever, but it seemed like he respected her independence.
...After he broke down crying about how he wished Mom and Norn could see Stella grow up.
That had been an awkward sight. It was especially awkward seeing a bunch of knights, rough looking adventurers, demons, and Rika panic and try to cheer him up.
But Stella earned herself some freedom.
With it, she started to do her own magic research and experimentation.
Mostly because she was burning to try things out after hearing what Rudy nii-chan was doing. But also because she felt really guilty about it.
Before she was reborn, she was already 17. She didn't know how old Rudy nii-chan had been before he was reincarnated, but she knew that right now, he looked like a kid bearing the weight of the world.
Even if he wasn't, she still felt guilty for just being deadweight.
More than that... Onii-chan was Onii-chan. Even though Stella could still vividly remember her other family, the affection Onii-chan had for her wasn't a lie. Even if it was a bit awkward calling a kid her Onii-chan... Even though she had been doing it for a while, the fact was that it was true in the end.
And he was sacrificing a lot to keep her safe.
Stella had seen it with her own eyes, after all.
Rudy nii-chan was the definition of a ridiculous cheat character. If he wanted to, she was sure he could run out there, scour the land, and get all of their family back together.
But he didn't. Instead, he stayed with Stella and built a safe haven for her. Not only that, but he watched her every minute to make sure she was okay, fed her, cleaned her, and did his best to make sure she was happy and had a normal baby life.
All of that while juggling the role of being a Guild Leader, Demon Lord, and Magic Researcher in his spare time... which he had by staying up through the night.
And it was having a toll on Rudy nii-chan too.
As the time passed, Stella saw her Onii-chan visibly aging before her eyes.
The kid who looked ten at most started getting taller. His cute baby face started getting more defined and his innocent and wide green and white eyes were turning sharp and mature.
A teenager instead of a kid. And all in the span of a few months.
Stella didn't know if it was because of the stress or what else, but she knew that it wasn't good. So she wanted to help relieve a bit of his worries.
And to begin with that...
Morning. Stella didn't know the date, but from the mental count she kept, it had to have been half a year at least. Long enough for some of her baby teeth to come in.
As usual, Stella blinked the sleep out of her eyes and then slowly sat up, taking care to steady her body.
Not that it would matter if she fell. Her overprotective Onii-chan had given her a magical pendant that kept her from getting hurt from falls.
...She learned that the scary way after trying too early to walk and starting to fall before being carefully plopped back on her butt.
But anyway, today was the day.
Rudy nii-chan had been busy recently talking to Mister Ruijerd and Mister Roland about something. He also left Stella alone a lot with Rika... Who spent most of the time staring off into space and writing things down on a piece of paper.
But right now, Rudy nii-chan was home. Just like every morning.
And just like every morning, he immediately noticed when Stella woke up.
"Morning, Stella." Rudy nii-chan let out a bright smile and then stood up to stretch. His silver hair shifted, catching the sunlight shining through the window on the roof. A handsome face that wouldn't lose out to anyone staring at her with a gentle gaze.
A perfect ladykiller smile. And wearing his 'Demon Lord' outfit of a fancy white suit and his gray scarf, Stella didn't have any doubt that girls would be following him wherever he went.
Just like they did with Aki.
...Stupid Aki.
Rudy laughed and then walked over to pick Stella up. "A little grumpy today, huh?" He smiled and then started tickling her.
Stella giggled and then flailed her arms, trying to get away. "Ba! Ba!"
Rudy's smile widened and then he held Stella up, staring into her face.
Stella stared back, still giggling a bit from being tickled. But she did her best to keep a straight face.
'Dang it, Onii-chan! I'm not a kid!'
Ah, wait. That was what she wanted to say. So...
Staring at her Onii-chan, Stella took a breath and opened her mouth to talk.
But then Rudy did first.
"...Babies really do grow up fast, don't they? In just a blink of an eye and you're already big enough to sit up by yourself. A little bit longer and I bet you'll be trying to totter around after me, won't you?"
A bitter smile. One with more than a bit of guilt in it.
"...Sorry. If your Onii-chan hadn't been so arrogant, we'd probably still be at home with everyone else. Maybe in a bit of a hectic mess, but we'd all be there. Instead, it's just you, me, and these bunch of misfits that decided to declare me as their Demon Lord of Salvation."
A lamenting tone of voice. Eyes that started to glimmer with unshed tears.
Seeing that, Stella reached out to pat Rudy's head like he did with her. After that, she said, "Is kay. Nii-cha twy hard."
The words were fumbled. She didn't have enough teeth, but Stella did her best.
Rudy froze.
Stella smiled.
And then...
"My baby sister is a genius! I knew it!"
E-Eh?
Rudy stared at Stella with a weird glint in his eyes and said, "You can talk, so you can understand me, right? Great. This means you can learn magic. And since you can learn magic, we can start adventuring. And since we can start adventuring, we can say goodbye to all of this hassle and just run away to find a way home so I don't have to deal with all of this stress. Right? You'll go with your Onii-chan, right?"
Oh. Oh no. Did... Did she just make a terrible mistake?
Stella thought that the stress hadn't gotten to Rudy nii-chan's head, but-
"Rudy, no!"
A familiar female voice. Rika-chan.
The stress seemed to have gotten to her too since she had grown quite a bit. Instead of a kid, she looked more like a first year high schooler. And wearing a pair of glasses and a suit, she gave off a mature vibe, unlike in the past.
...Though the reason for that mature vibe was-
"Lord Rudras is the core of this kingdom! If you leave, Rika will have to deal with everything on her own!"
"Then deal with it! You were some Great Demon Empress or something, right? Run it for me!"
"Rika did that once! Rika is not doing it again!"
"I'll become the Magic God Emperor!"
"Rika calls your bluff! If you want to, Rika will start the paperwork and planning!"
"Gah!"
Stella blinked and then looked at Rudy.
He noticed and looked back. "Yes, Stella?"
"...Nii-cha. Baka."
"Kuh! T-That..."
Rudy rigidly walked Stella back to her crib and set her down. After that, he slumped over and covered his head. "Stella called me a baka. My cute baby sister said I was an idiot. It's over. I knew it. When puberty hit, I'd inherit Dad's idiot ball. Uuu..."
Rika adjusted her glasses and then shook her head. "And Rika was so worried about Rudy turning into that scary Handsome One as the Magic God Emperor... How silly."
Stella sighed.
Yes. This was her life now. Stella Notos Greyrat, younger sister to Rudeus Notos Greyrat. The Demon Lord of Salvation who created a kingdom to house and rescue victims of the worldwide spacetime disaster. Demon King Rudras, leader of the White Knights.
...And a baka Onii-chan who seemed to be the cheat protagonist of an isekai light novel.
-SNG-
OMAKE
"STELLA!"
"Nii-cha! No!!!"
KABOOM.
[author] Okay, I lied a bit. Writing from Stella's POV is fun and a good way to time skip. We'll be going back into Rudy's POV now though about half a year from the start of the incident.
[/author]