Naruto: Ren the Sealmaster

"There. That's done." Ren tensely said after finishing drawing the gravity seals on Hinata as he stiffly took her jacket from the ground beside her and covered her naked body before standing up and taking a large step back.

He gulped. There must be something wrong with how chakra interacted with physical and mental maturity in this world. Now that he had a proper look, Hinata was... a bit too developed for her age.

'Just don't think about it. All is as it should be.' Ren embarrassedly tried to keep his gaze on Hinata's forehead and damn if it wasn't hard.

Hinata lifted her body into a sitting position, her face redder than ever as she quickly pulled the jacket tightly around her body, vainly trying to disappear within it, "Mhm." She looked down and absolutely refused to meet Ren's eyes.

"Right." Ren awkwardly coughed... "I'll go and let you get dres-" He abruptly stopped, noticing that her wide eyes were not looking at the ground but instead, they were aimed directly at his crotch and flushed from embarrassment. He had just finished drawing seals all over the girl's naked body. His reaction was only natural!

He woodenly turned around and... ran away at his fastest walking speed.

...

Later in the day, Ren sat at the Ichirakus, absent-mindedly fiddling in the ramen bowl with his chopsticks while his cheeks still felt hot and he only hoped they were not red.

It was bad enough that he had to return once Hinata was dressed and explain to her how having gravity seals was going to affect her. They were both acting like embarrassed teenagers, refusing to look at each other while they awkwardly talked.

Ren would love to say that he was cool and badass, taking everything in stride, and he certainly tried his best... but his best just wasn't good enough. At that moment, his mind just blanked out and he wished the ground would open and swallow him whole.

Now that he regained some of his cool, he was wondering why they didn't have a class to deal with body shyness in the academy.

Worse yet, because of the gravity seals, he needed to monitor Hinata's well-being. So, he scheduled a training session for tomorrow. He already felt mortified just thinking about it.

But it was necessary. He told her she would feel very uncomfortable in the first month as her body grew used to constantly being under slightly stronger gravity.

He remembered that he couldn't even fall asleep in that first month unless he was so exhausted he just fainted. That constant discomfort might not hurt. But it was always there. Like a persistent itch that was impossible to scratch, making a person unable to relax no matter what.

Not to mention, being under heavier gravity was physically tiring even if the mind was not really registering it because the pressure was barely noticeable at all times, growing heavier as the user got stronger.

Ren was sure that Hinata would come to the training tomorrow with black circles under her eyes. He didn't intend to train her. He was just going to knock her out and let her sleep for a few hours on the grass to make it easier on her.

He knew he would have appreciated it if somebody did that for him when he was going through the experience. She was going to feel like absolute shit for the next few weeks so it was Ren's duty as her teacher to make her discomfort as comfortable as possible.

In the end, it would be all worth it for the girl. He explained to Hinata what his gravity seals were and how they worked and the girl understood just what a priceless thing he was offering her.

Unlike the fanfictions from his previous life, there was no such thing as gravity or resistance seals in this world. It's why Ren had to create his own.

Most people in this world did not even know what gravity was. They did not study physics or chemistry in the schools over here. No such thing really existed.

Kids in the ninja academy focused on learning how to be a ninja and the less said about civilians the better. They were happy if they learned how to write and read. There was a reason why so many civilians sent their kids to the ninja academies in the ninja villages. They simply provided superior education and a chance at a better life.

This world was still barely past its medieval stages. It was also still a feudal society. And Newton did not exist here. There was no such thing as Newton's laws. Or any other laws of physics. 

Oh, these laws still affect the world. But the natural sciences in this world were still in their infancy, not even having a name yet. People know that if they jump, they will fall to the ground. But they had no idea why and didn't really care to think about it.

The theories about gravity did exist. Some of them were surprisingly advanced. Ren checked. But they were high-level ninjutsu or fuinjustu stuff that most ninjas did not even bother looking at.

Scientists did try to understand the world. But the civilian scientists had a hard time getting funding so sciencing was pretty much a hobby for nobles. It was not a popular hobby either.

While the ninja scientists mostly focused on the supernatural nature of chakra and researched how it worked and affected the world around them.

That's why Guy used weights. He simply did not have a better alternative.

But unlike the gravity seals, the weights were limited. They did not put even pressure on the body, making it grow in strength disproportionally for different body parts. The stronger a person got, the more weights he needed for further growth but weights were bulky so there was a limit to how much a ninja could wear before they became a hindrance. The heavier the weights were, the bigger they were and it wasn't as if Guy could strap house-sized weights to his ankles and live like that.

There was a limit to how far a ninja, even one as crazy as Guy, could take weight training.

With chakra, a person could theoretically enhance their body as long as the body registered it needed to grow stronger. It was proven that chakra allowed the body to evolve beyond human limits and slowly become stronger under strain. Guy was a very good example of that.

But even then, the man got to his current physical peak and now, no matter how many hundreds of thousands of push-ups he did, his gains were minimal. Because his body is too strong and the pressure from a 'normie' training like that is just not enough for his body anymore even if he trains all day. Even if he wears the heaviest weights he could get his hands on.

It's simply not enough pressure on his body. But he doesn't have a better alternative than just doing push-ups and running around the village with weights. It's probably why he always came up with such ridiculous challenges for Kakashi.

The man definitely wants to get stronger. But it's maddeningly slow-going at his level.

That's why Ren's gravity seals were so special. With higher gravity affecting the body, it was always under pressure evenly on every part.

Ren should be able to grow to Guy's physical prowess and then keep going further without stopping. The seals would always push his body just slightly beyond its limits, allowing for a slow, constant growth even if he did not exercise.

Of course, reaching Guy's level would take him years. He wouldn't be near that level for a long time yet. 

But the potential of these seals was immense and Hinata understood just how beneficial they would be for her. She also understood how precious they were and why their existence had to stay quiet.

Everybody would covet them if they knew about them. Something that could allow a ninja to physically grow with no limit by simply being alive? Ren would have kidnappers after him from every major and minor village alike, Konoha included.

It sounded far too good to be true and Ren was still doubtful he happened to make something so convenient. There was bound to be some kind of problem in the future that would limit the growth.

No way he could just become Saitama. The world was not so easy.

Then again, Kaguya was physically much stronger than even Guy. She tanked Naruto's mountain-shattering punch with her face when he was in his Sixth Path Kurama Chakra Mode Senjustu cheater bullshit given to him for free by his sugar daddy Hagoromo... and it did not even leave a small bruise on her.

Her body was also evolved to that level by the chakra fruit. She didn't get it through training. So, technically it was just a chakra evolution of her physique.

Ren's seals did something similar. Just in a very, very, very slow way. So, maybe?

A man can dream, right?

Speaking of Naruto, Ren's thoughts were suddenly interrupted as something orange sat next to him and rudely poked him in the arm.

"Ne, ne, if you aren't going to eat that ramen just give it to me, uncle!"

Ren's eye twitched.