Chapter Text
"Kohaku, let's have a discussion," Senku told his sister.
"No, we are not," Kohaku replies, walking out of her room and pushing Senku into the small hallway. All around them were whispers and the prying eyes of those listening to the lecture the head of the household was given that day.
"Yes, we are," Senku says, doing the same as her until they both end up in the living room. "We both know you can't leave the apartment without my supervision."
Kohaku hissed at him; slowly, her form changed. Her teeth turned into fangs, claws came out of her hands, and she was on all fours like she wanted to kill. "You can't tell me what to do!"
"Yes, I can. I'm in charge." Senku said, unfazed by how Kohaku changed and morphed into a creature. He was familiar with her efforts to look tough but they did not entertain him.
"You understand why you can't go out." He explained further, gesturing to her entire appearance. "I'd rather make sure you all aren't taken away." Then, he announced it to everyone in his household.
The other sisters stepped over to Senku, thinking his usual lecture was over. Kirisame seemed unfazed by how Senku talked to everyone, and it wasn't like it was the first time she'd heard this talk. Ruri seemed bored. Knowing full well that this lecture was never going to direct toward her, she needed to stay in the bathtub. Giving Senku a headache with the water bill. While Suika nodded along, knowing she was the second most likely to get a scary lecture, as Kohaku did. It was to where they had to put a bell on her.
No one in this household was normal by any means. Senku lived with his four sisters. All of whom are mutated monsters that his parents experimented on.
"Alright, let's get dinner situated. Kirisame you're helping me today." Senku said as he grabbed his apron and tossed one to his eldest sister.
"You got it." She replied in a soft tone and put on the garment. Then she took a pair of sunglasses from her pocket and put them on.
They knew Senku was unaffected by Kirisame and her odd powers. Senku had fully committed to disregarding his body to determine how her powers worked. Though they never got far, turning into stone wasn't as fun as he thought it would be, and Kirisame put on glasses whenever she got too close to him. The poor girl gave him scars from his last encounter with Medusa.
Senku wanted to figure out everything about his sisters and their misfortunes—even his twin and how unalike they were.
Kirisame was cutting up the vegetables while Senku prepared the fish. He learned a lot since living alone with them. Most of them were born and raised in labs. His sisters didn't know how to use chopsticks or tie their shoes without Senku's help.
As tragic as it felt, Senku did his best. Finally, a benefactor gave them an allowance to live, so Senku did everything he could to keep them afloat despite their issues.
He heard the bathtub run, quickly leaving the fish for Kirisame to clean. He ran down the hallway towards the bathroom and opened the door. Right in the tub was a fishtail he knew all too well.
"Ruri, we talked about this!" He huffed and turned it off.
A head popped out of the water's surface; blonde hair and blue fish scales were all Senku could see. Knowing full well that she wasn't making eye contact for a reason.
"You know your baths are expensive." He said to her like this was the millionth time.
"I knowwww." She said, again sinking down into the water.
Great, now they had a bath already made, and it wasn't even dinnertime. "You're going to wash Kohaku's crazy hair today." He told her as he walked out of the bathroom, with many songs of protest being sung to get him lax the punishment. None of that worked on Senku, either. Since he was a baby, he's heard her songs and knew what she wanted when she sang out. Unfortunately, his sister, the siren, was not getting him soon.
"Senku, I turned the fish into stone!" Kirisame yelled from the kitchen. Oh, how the fun never ended in his home.
Senku ran into the kitchen. At the last moment, he could only see a floating potato. He crashed into it. Senku landed on his ass, but he could now see that he had knocked down his sister onto the ground. Senku picked up Suika and dusted her off. Her ability was the only one that Senku fell victim to.
"I'm sorry, Senku! I just wanted to be useful," She said as she held a potato that needed to wash.
"It's alright. I didn't see you." He told her, taking the potato from her. "I have a special mission for you. I need you to get Kohaku into the bath." He instructed her. Which soon enough made her turn invisible. Senku could only hope she was doing what he asked, but he was talking about this Kohaku.
Senku went to Kirisame's side and looked at the damage of the fish-turned stone.
"How?" Senku asked, like Kirisame had any idea.
But with little time to think it over, Senku grabbed a chemical he cooked up right for this experiment. Of course, he, a super genius scientist, needed to be prepared for any chance he got to experiment on everything.
"What if it doesn't work?" Kirisame asked as she peered into the glass containing the strange liquid.
"We cook a different fish. But more importantly, if this works Kirisame, we can cure your petrification." Senku said.
Helping his sisters was his ultimate goal. It was to cure all his sisters so they could live like ordinary girls. So instead of hunting for exercise, Kohaku could play sports. Kirisame could look into her lover's eyes and not turn him into stone. So Ruri wouldn't dry up whenever she left the bathtub for a few hours. He wanted to ensure Suika was noticed and not trampled over.
He had many lofty goals, but it was all for the sake of his siblings.
He poured the liquid onto the fish and waited for it to do something.
Nothing.
"Sorry to say Kirisame, but we own a new paperweight." Senku sighed, another disappointment.
But she patted his back, which made him feel a bit better in the end. But, of course, things don't always go his way, and what was fun about his work was figuring out one step at a time. Now if only he were old enough to buy alcohol to make this work.
Despite the turn of events that led him to reconsider his approach to helping Kirisame out with her powers, he continued. Dinner needed to be served.
—
"Look, alive girls!" Senku called from the kitchen as they stumbled their way into the kitchen. Everyone besides Ruri, whose turn it was to help Senku prep for today's breakfast. "I've got some news that'll knock the socks off you."
"Well, get to the point." Kohaku huffed as she poured herself a glass of orange juice.
"We're going out," Senku announced as he put Suika's and Kirisame' plates of food in front of them.
"Out? With everyone?" Kirisame asked her brother.
"Yup, you better get excited." Senku smiled as he poured Suika a glass of juice.
This was the first time they would go out together. Usually, Senku could only handle one sister at a time. They would help him decide on dinner, small gifts from stores, and anything to experience the outside more.
But it was so stressful for Senku; he had to keep tabs on everyone and their strange issues, like how Ruri looked fishy if it was raining and the humidity was high. Kohaku had too much energy for Senku and his scrawny ass to keep up with her. Suika got lost often, making it worse when she accidentally turned invisible by habit. Kirisame was the only one without incident, but that was due to the older one's more responsible nature and fear of turning a random person into stone.
"That glint in your eye! You have something!" Suika said. She knew her brother well. Being his little assistant had its perks of knowing when he was scheming.
"That is correct, Suika. I ordered some things to help us out a bit." Senku talked to the closet to return with things. "Welcome to the wonders of the internet! We can get all sorts of things shipped right to us."
Ruri peered at the packaged box. "So what's in it to make it so useful?"
"Well, we can start off with you." Senku opened the box and took out several containers of makeup. "Tada! Waterproof makeup. With this, you can go out without looking all scaley. We just need to apply this to your skin, and even the humidity won't bother us."
Ruri got up from her seat and grabbed the makeup from Senku. "So I can just go outside? Without any worry?"
The other sisters started to get excited, but Senku had to quell it down. "We still need to worry about rain, but hey, that is significantly better than covering you head to toe like we've had to do in the past."
"Senku, what did you get me!" Suika asks, all excited and standing on her seat.
Senku took out another item, which was a wrapped-up poncho. Which made Suika squeal at how bright and colorful it was.
"Thank you Senku, it's so pretty and shiny!" Suika quickly unwrapped it to put it on.
Senku didn't have the heart to tell her that he got it so he could shine a flashlight on her and be able to see her better in the dark. Instead, he just allowed her to hug him and moved on to the next person and gift.
"For Kohaku, we have this hoodie," Senku announced
"Ha! like a new hoodie would tempt me into your schemes Senku."
But that minor rebellion was quickly shut down when Senku pulled out a cat hoodie with paws and ears. It was perfect for keeping Kohaku distracted for hours at a time.
"This is the cutest little thing!" She said as she took it from Senku to try it on.
"Hey, no problem at all," Senku smirked, entirely winning her over. He knew how to win each one over. Senku used the hoodie with paws and ears to keep her distracted for hours and fully cover her so nobody would suspect a thing. The ears would cover up her real ones, and the hand covers were big enough to catch her claws. It was brilliant the things he could get with clicks of buttons.
"Kirisame, I got you some new sunglasses." Senku passed the last thing to his older sister.
"Thank you," She said with a tiny smile, "They're perfect."
The glasses were too big so they could cover Kirisame's line of sight nicely. Senku could see they were falling off the bridge of Kirisame's nose, but she was good at keeping them on her face despite the inconvenience. He would make sure to correct them for her later.
"Alright, enjoy your things and eat like hell now." He rushed the girls back into their seats.
"What are we going to do, Senku?" Suika asked first before settling down again.
"We're only going out for ice cream. At a new place down the street." Senku told his sisters, which caused a lot of thanks and excitement. "Yeah, eat now, then ready. I want everyone fully guarded." get
With those words, suddenly breakfast was a race. Before Senku could even start counting the seconds, the girls were ready to go out as a family. Their only brother was the one lagging. Senku was the last one out the door, so he got to lock it, and there they went.
The morning air was lovely and calm while the sun shone warmth onto the family. They lived in an apartment close to the beach; they had an obscure view of it, but seeing it with their own eyes was more magical. Senku could appreciate the wind in his hair and the laughs of his sisters in the air.
Suika was rushing ahead, but Kirisame kept an eye on her. Following her and ahead of everyone else. Kohaku and Ruri were talking amongst themselves, and for once, Senku felt some peace as he stayed behind.
Soon enough, they found themselves in front of a newly opened ice cream parlor as Senku promised.
"I want watermelon!" Suika exclaimed as she tried to rush into the door.
"I want strawberry!" Kohaku played along with her younger sister and entered the building with her.
Senku held the door for Ruri as she joined the shop, but Kirisame stayed behind. "You aren't coming in?"
"Let me bask in the sun for a bit. Get me a cone if you can." Kirisame said as they sat down on a nearby bench, which led Senku to leave his big sister alone.
Inside was better than Senku predicted. Ruri was still deciding which flavor to choose, so she got three at once, wincing when she realized the flavors didn't taste well together. As true to her name, Suika got a cone of watermelon ice cream in the act of the cutest cannibalism. Kohaku got strawberry but a mountain of toppings to be added with it. Senku just laughed at any misfortunes they had but paid for their cones. Then choosing his own and his older sister.
Then there was a scream outside. The first person to turn their head was Senku, his body moving on its own as it made its way outside. He needed to know what happened.
His sister was covering her eyes, sunglasses on the floor, and when Senku looked up. There stood a tall statue.
“KINRO,” yelled a young blond boy nearby.