Changes at sea.

"So… How many people did you do it with?" Karin asked.

"...What?" Naruto asked, dumbly.

"How does this link thing of yours work?"

"Ah." Naruto answered. "Still not sure, the two times I pulled it off, I wasn't really thinking very hard on it. Or thinking at all."

"It's only Sasuke and Sakura. If you remember, I tried with Orochimaru, but nothing happened."

"Ah. I see." Karin said. "It… sounds really useful."

"Sure." He nodded. "I would have loved being able to teleport earlier. We… We could have avoided many things."

Karin stayed silent for a while.

"Do you think we could try it again?" She asked hesitantly.

"You and I?" He paused. An amused grin spread on his face. "Why is that? You want yourself some flashy weapon, don't you?"

She avoided looking at his face. "…Yes. That's it. I'm curious."

"Sure, let's try it out, then."

The first attempt failed.

Karin looked disappointed, but ready to stop there.

"Nah, wait a second."

"…You want to try again?" She asked, hesitant.

"Yeah. Let me try to focus on what made it work in the first place."

He kept a hand over Karin's, sitting at the small table they built in their room.

What made it work with Sakura?

What had made it work with Sasuke?

What was different here…?

They had been in danger, in both situations. Was that it…? It could be, but then he wouldn't be able to reproduce it.

Danger… danger… danger.

There had been a need for a weapon. A weapon, not just to kill, but to protect.

To protect people he cared for.

And there had been trust. He trusted Sakura.

He trusted Sasuke.

And he trusted Karin.

He wanted her to live. To grow, and have a chance to be happy.

She was Karin, and he would do everything in his power to ensure that.

Naruto felt the same feeling again. His chakra and Karin's… connecting. Similar, but different.

He pulled.

In a flash of thunder, a pair of gold bands appeared around her upper arms. Karin's presence settled somewhere in his unconscious mind.

Naruto felt exhausted. Karin's smile was blinding.

She tackled him into a hug, making both of them fall on the floor.

Middle of June came.

The heat started to rise. Naruto gave up on wearing shirts, trusting his chakra to protect him from the worst of the sun rays.

The sailors were slowly learning how to channel it, and soon enough, they joined him in that. The girls settled for bikini tops.

If Naruto had to describe the ocean today…

'Empty'.

'Nothing in sight.'

At all.

Before, there had been the occasional rocky mountain island… Some flat deserted ones, even some with trees.

Right now, there was nothing. No waves. Nothing on the horizon.

And of course, it had been weeks since they had last seen another ship. Naruto wondered what the sailors were thinking. He had told them about his ability and that they were not truly at risk of not coming back…

But he had the feeling they would be just as stoic if he didn't have it.

The sea was beautiful, though, shining bright blue, looking almost flat.

Karin and Sakura were passing around a sphere of pure water and chakra, trying to keep it stable with every throw.

Takaya was sipping on some rice beer, — he had brought liters of it in a seal-jar — looking entirely at ease.

Naruto was sitting next to him, in comfortable silence. They had been weeks in each other's presence for weeks, and there was no point in constantly talking.

He had a question, though. "How deep is the ocean floor?"

"Ah, that would depend. We are in the North Ocean, so… Hm, I think the average depth should be at around four kilometers."

"How deep is this?"

"Well… No human ever managed to get deeper than five-hundred meters, and that's using chakra. Let's ignore that. After two kilometers, you would start feeling very cold. I mean, your eardrums, lungs, likely your ribs would have been crushed long ago, but yeah."

"Ah. I see. Are there creatures living down there?"

Takaya snorted. "Creatures is the right word here, son. These things often look like they're from another planet."

Karin was experimenting with the gold bands.

Without wanting to brag, she had a knack for experimenting. So she figured out what they did faster than Naruto would have on his own.

Simply put, it seemed they made anything chakra made 'permanent.' Things slid in place, and a chakra construct became... natural, for lack of a better word. As though it were part of the world already.

A seal, a construct…

Using the bands on these made them rely on natural energy instead of human chakra. There were still limits, in the sense that a seal would need to replenish if it pulled too much energy, but…

This could change everything.

Naruto dubbed the ability "Natural Order".

It wasn't as egregiously bad as some of the other names he had come up with before, so Karin ended up using it.

First thing they did was use it on the propeller, so that they could keep it on permanently, as the amount of energy it required was pretty low.

It also had the added bonus of making it stronger, more effective. They would make good use of it.

That should likely cut the travel time by a large amount. Half, maybe.

Because it seemed the wind had something against them, most of the time.

Naruto went back to tinkering with seals with redoubled fervor, after that.

It seemed he could use a fraction of the ability himself, but in his case, it worked better with his own seals or the weapons he summoned personally. Karin didn't really seem to have this limitation.

The first thing he did was reinforce the walls of the training room, and strengthen the fireproofing seals. Not having to recharge them every night would be a blessing, too. This should reduce the risk of destroying anything on their boat.

He still had built no separators between the rooms, but all three of them had taken to late-night planning in their futon, ending up sleeping in what looked more like a pile of bodies, once the morning came.

He'd get around to doing that. At some point.

The hull could use stronger maintenance seals…

He could likely copy the propeller seal and build a second one, since they had left with a lot of raw materials.

Maybe a location seal could be used to pinpoint their approximate position…

And then he could synchronize it with the paper map, maybe?

Soundproofing the boat could work, too. Inside, outside as well?

Something to keep the temperature more constant?

And…

What if he enhanced clothing and equipment with sealing?

Sakura was already sleeping.

He brainstormed with Karin, who endured it with a fond smile, taking notes, and coming up with twists on the ideas, as well as new ones… until the later hours of the night.

Then they passed out on the floor.

When Karin woke up, it was late morning. Sakura was gone.

She let out a muffled noise when she realized Naruto was spooning her, his warm body pressed against her. He was deep asleep.

He had a tendency to move a lot during the night, so she assumed he was the one who had rolled over.

Then she realized something else. Naruto was hard. Very hard.

She blushed bright red, his erection poking into her ass. Karin felt heat between her legs, her traitorous body responding.

She…

Karin moved away.

He mumbled something in his sleep and got closer again. Karin felt his breath down her neck, and a strong arm wrapped around her. His length was prodding her ass again.

She ignored the ache between her legs, waited until he rolled away, still asleep.

Karin didn't enjoy the sudden absence as much as she thought she would.

She went for a very cold shower.

When he was not testing out new sealing methods with his clones, — where his copy of Suijin's notes really came in handy — Naruto practiced chakra control.

He understood how Sakura glided across the water, but he could not replicate it. The best he could do was propel himself loudly.

He wanted to get to the point where he could apply a seal without ink on any surface. Writing seals by hand every time simply took too much time.

Naruto was progressing, having cut down the numbers of supporting symbols that he needed to write down for a given seal by half on average.

The "Laundry Seal" he had created in the last few days was pretty helpful, as you just had to write it on a barrel, connect it to a source of water, — could be another seal barrel — a soap or cleaning agent, throw your clothes in it and they would get cleaned in less than ten minutes.

It wasn't going to change his world, but he could likely earn some decent money with it. He just had to make them permanent and sell them after.

He would put the finishing touches on his diving suit, soon.

Making a map turned out to be pretty straightforward, too, if a bit lacking in terms of precision. One location seal was put on the front of the boat, and another at the back. Both working with natural energy.

It was easy enough to extract data about your current position from a location seal. Then all he had to do would be to make a copy of the world map, split it into a grid, and synchronize the boat's position on it.

And since it worked for a boat, there was no reason it wouldn't work on a personal scale, by attaching the seals to a pocket watch, or anything a person could carry, that could also fit a paper map.

Easy enough.

They were moving much faster with two propellers.

According to the map, they would be at around the midpoint, and they were only nearing the end of June.

The sailors had a more precise idea of where they were going now, since Naruto actually had to tell them that at some point.

He would likely offer to teleport them back, once he was done, sparing them another two months trip.

The boat could stay here, as it might come in handy when it came to navigating this oceanic part of the world.

They still had a month, then, Naruto thought.

One month without any probable danger in sight… At least not in the form of stronger enemy shinobi.

He had wanted to stop, but the appeal of enhancing his growth, at a time where he felt he was not seeing too much of it…

Well, it was starting to sound more and more appealing.

Orochimaru was not here, but they had established what kind of ancient seals would be a decent fit.

Maybe now was the time to complete another set.

"So yeah, that's what my… tattoos are."

"…You've been carving your body up with a dagger in order to force your body to grow…?" Karin asked, horrified. She had known he and Orochimaru were experimenting with something that led to Naruto recovering for days on end, of course, but none of them had given her more detail.

Sakura said nothing. She had wondered what the sort of minimalist symbols on his body were for.

"I mean, anything sounds bad when you put it like this." He said.

"Anything? Give me another example, then."

Nothing.

"Could it work for me, too?" Sakura asked quietly.

He stopped to think about it, then winced.

"I'm not sure. It's an Uzumaki clan art, and let's say that their most defining characteristic was a strong Yang chakra, and resilient bodies. I… wouldn't risk it." He said, scratching the back of his head.

"I see." She said, not too disappointed.

"…What about me?" Karin asked.

"Ah." Naruto thought about it, hesitant. "It… might work. Just… The process is a bit rough."

"How rough?"

He sighed. "Look, I'll let both of you see what it's like next time."

"…Next time?" Sakura asked.

"Yeah. Now seems like a good time to do it. Apparently, their effect might be stronger during puberty." Or so Orochimaru had said, but none of them were certain of that. "But still, you should really think about it longer. It might also fuck with your mind a bit."

"…Like?"

"Well…" They made him a bit easier to anger, more eager to fight… and hornier apparently. "They will enhance certain aspects of your personality."

"You said 'enhance' though, not change." Sakura said.

"…Yeah. That's true. And you need time to recover from it. It can be up to a full year… maybe two years, with less chakra capacity."

"…It's not something Uzumaki are lacking, though." Karin said, folding her arms.

"No, but-" Did Karin think he was trying to play some reverse psychology trick on her… or was she doing it on her own?

"And both you and Orochimaru-sama are probably going to get into more trouble, won't you?"

He pursed his lips.

"Then, I want in. Show me how to do it." Karin finished.

He gave up.

'Okay. Maybe I'll steer away from anything Fertility related this time. I'm on a boat with Karin and Sakura. I don't want to end up fucking things up.'

He was sitting in front of Sakura and Karin, wearing only a towel.

Karin was definitely staring at him, likely trying to understand how his seals worked. It was good that she was being proactive about it. He nodded in approval. She looked away.

There were three important seals he wanted to complete before they might lose in potency.

He was still growing for now, but he knew it wouldn't last for long.

"All right, watch closely then."

The girls nodded. He drew most of the symbols in ink on the floorboards.

Then he summoned a ceremonial crystal dagger.

"Takemikazuchi."

Another Raijin.

God of Thunder. God of Swords. Conquest. War. Power.

He carved the seal right below his left shoulder, opposing Raijin, on his right shoulder. With almost no sound.

He pulled the symbols on the floor into the new shining mark. He felt a bit more unbalanced.

Naruto drew the next set on the floor, patiently. Sakura and Karin watched in silence.

"Takeminakata."

God of Wind. God of Hunting. War. Strength… Ah, it was Fertility too.

He winced. There really was no escaping it, then.

Naruto absorbed the seals on the floor once more. According to old legends, Takemikazuchi and Takeminakata were gods who fought each other.

He could almost believe it, right now.

Both marks were burning, more painful than the rest were.

He must have been looking pretty rough, because both Sakura and Karin were starting to look kinda worried.

"I'm fine. I'm fine."

Why was his voice so rough…?

Alright. Another one to knock down. He drew the seals very carefully.

"Susanoo-no-Mikoto."

God of Seas. God of Storms. Thunder and Lightning. Wildness. Moral Ambivalence.

This should allow him to rein in the other wind and thunder kami, who are supposed to serve under him, according to legend.

If this holds in reality, he will have to see.

Susanoo fits along his spine as well. When he pulled it in, he barely managed to suppress a scream.

"…Is it over?" Karin asked, ready to rush in.

"Almost." Naruto wheezed.

"Tomoe." He carved one into the left side of his lower back.

"…Tomoe." He carved another one on the right side of his lower back.

"Tomoe." Last one went along his spine, too.

"I'm done." He rasped.

They were the most basic of the ancient seals, not requiring any surrounding seals, as the intent for it was one thing, and one thing only.

Amplify the others seals.

He felt very sleepy, all of a sudden. There was a lot of blood on the ground. Somebody caught him.

The next few days were spent in a daze.

It had never felt so rough before. Sakura was reading a book next to his bed.

"We told Shinjiro and the crew that you were feeling a bit under the weather, it should only last a few days." She said, keeping a careful eye on him.

"Thank you." He said, weakly.

"It's nothing."

They lapsed into silence. She turned a page.

"I think I'm gonna pass on the seal carving thing." Sakura ended up saying.

He laughed, before coughing. "I don't blame you."

"If it puts you in this sort of state, while being both Uzumaki and a Jinchūriki… I don't really want to know what it's going to do to me. Or my chakra levels."

"Fair enough."

"Karin still wants to do it, though."

"…Really?"

"She can be kind of stubborn."

"Understatement of the century."

"Is it me, or is the room freezing?" Naruto asked, shivering, in the middle of the night.

Karin looked around in confusion. "No, at all. It's actually very warm."

"Ah. Then I might be a bit sicker than I thought."

"Is there anything I can do for you?"

"No… No, I don't think so. I'm not done with the temperature seals. Maybe they would have helped."

Karin huffed. "Look, this can wait. Plus, it's not actually cold out there. Your body temperature is higher... which means you feel cold, I imagine."

"Ah, shit. Can you get me one more cover?"

"I don't think it's going to change much." She answered.

He kept shivering, not saying anything. This was going to be a long night.

"I…" He heard her hesitate. "I'm going to help you, okay? Don't turn around, please."

He heard the sound of clothes being removed and felt himself panic. What was she doing…?

Karin lifted the covers of his futon and slipped in.

"Karin… Don't. I'm not wearing any-"

She embraces him, her arms around him, pulling herself tight against him.

Apparently, she's not wearing anything either.

"…I know you'd do the same. Let's sleep, then."

In the end, he couldn't really sleep or even turn around.

He did feel warmer though, inside and outside.

Naruto did feel that it was worth it, once he recovered. It seemed as though his body was just… working better, all over.

Including things like faster recovery, less need for sleep and senses that were sharper. Not expected, but apparently, the Tomoe seal was much more potent than he had thought.

Two more hours awake every day was probably one of the most significant changes.

Over the course of fifty years, it was the equivalent of five more conscious years.

Now, he just had to put it to good use.

"Thanks for last time, Karin."

She didn't meet his eyes. "Don't worry about it."

Naruto's chakra reserves definitely felt smaller than normal.

Well, he wouldn't need a lot of it for the foreseeable future, and it was still more than double what most elite shinobi worked with, so he wouldn't complain too much.

In the meantime, he buried himself in other projects.