Serotonin {Senku x Reader}

Part 1 - Rebirth

Y/n wasn't anything truly special, by her standards. She had had a normal life, went to school, came home, ate dinner, and went to bed. She had above average grades in her class, but that was due to how much she read. She read any spare moment she had, to the point where she was  alone because of it. But Y/n never felt alone, because the books were her friends, and the characters in them. She had always longed to live in a different world, one that was her own. She lived through different stories.

And as she looked around her, she realized that it was her world. She was the last person left.

The first few days were were hell. Finding water, food, and making a fire was much more difficult than how her books made it seem. At least she had read Hatchet. Eventually, she made a decent lifestyle. She made a camp by a stream, and went out to gather nuts and berries daily. In the evening, she would create a campfire with techniques she had learned about in a survival book she had read. She had achieved survival, but it was a constant effort. The winters were hellish, even when she saved up food. She had found ways to hunt, she turned wine into vinegar, and pickled meats so they would sustain her. Even so, it was a truly horrid experience. She was glad she had woken up in spring. But her constant survival effort meant she had no time to look for anyone else, not that she'd know where to look anyways. For the time being, everything was lonely.

Until she stumbled on her first statue.

Eyes wide open, mouth gaping in shock, a little girl who she had never met. She was a stone statue, covered in moss, likely unaware that she had been caught in stone for so long. Y/n realized that that was how she had entered that void. Out of respect, she made a little necklace out of vines and left it on the girl, promising to return and find a way to bring her back.

Weeks passed, and the feeling of loneliness and despair overwhelmed Y/n. She had made a small hut, a fireplace, and clothing for herself. She was comfortable, going out to find berries and mushrooms which she deemed were safe to eat every day, and eventually figured out how to make clay pots from the thick mud she found in the stream.

Clothing was an interesting science in its own sense. Y/n didn't know how to make clothes, she was never an artist or seamstress, but at long last, she settled for some shorts and a shirt. She had never liked dresses, and shorts offered more mobility. In the winter, she'd wear layers of loose pants and jackets.

She was surviving, but without her books to comfort her, she was slowly going insane. She first tried making songs, drawing in the dirt, but it offered her little comfort. She then decided to make up stories to tell to the stone girl, which she found to be much more satisfactory. It made her sad knowing the girl would never hear them.

It seriously frustrated her. She would often scream in frustration, cry once she was tired, then move on to keep surviving. It was an endless cycle of creation, destruction, and more creation. It was difficult, but she grew accustomed to the feeling. After all, she was the last human on earth.

By this point, Y/n was sure she'd be by herself forever, with the exception of the stone girl. She had brought the girl back to her home, keeping her in her hut, making sure she would stay warm. She decided to call the girl Val, thought she was quite sure Val wasn't her real name. In her mind, Val was a sweet, timid girl, but a mute, which was why she never answered when Y/n talked to her. Y/n was glad she had Val. 

Y/n wasn't sure how long she could go on. As much as she loved Val's comapany, it would always be a one sided relationship.

 She carved the days on a tree with a sharp rock, and when she hit six months, she'd move on to another tree. Soon enough, she had filled up two trees, and found she had aged another year. When was her birthday? She had no idea how much time had passed, so she would never know. To cope, she made the day she was awakened, the day she was reborn, her birthday.

After two years, Y/n found that surviving was easy. Keeping her spirits high was the difficult part. She would make new stories every day for the girl, and even made some clothes for the small girl. A cute, short dress. It worked, though the feeling of bliss and completion was only temporary.

Y/n had filled up six trees by now. Three years. She was now 19, not that it mattered. She wondered how she had survived that long. She wasn't remarkably strong, seeing as she never excercised in the modern world, but having to go out and gather food everyday and using brute force to hunt really build up her stamina and muscle. She also didn't have any particularly useful survival skills other than the few books she had read on the subject. She was simply grateful that she was still alive.

And so the three years trudged by, non stop gathering food, telling stories, and making new ones. Y/n wished she had paper to write it all, down, but attempts she made at making paper where futile. Either way, she supposed she was content.

It wasn't until that third year, however, that she met him.

While she was out gathering berries, she heard a rustling in the bushes. She held her crudely made spear in hand, in case it was a boar she could eat. But what walked through those shrubs shocked her more than anything.

Ruby eyes, snowy white hair, tipped green as if kissed by nature. A slight build, and a sharp gaze. The boy that wore animal hide froze when his eyes met hers. Y/n opened her mouth to say something, but the words wouldn't come out. For a moment, she felt nothing— the calm before the storm. The birds chirping seemed to fade away, along with the rustling leaves of the trees.

Then she heard the first words spoken from another person in years.

His voice.

"Today is May 28, 5738."