Medical Ninja Beast: Umibozu

The waves looked fierce, but Touma made no move to dodge. He could clearly see a distinctly humanlike expression on the surface of the towering swell.

Just as he'd expected, when the wave washed over him, it didn't feel heavy. Instead, it was as gentle as a caress.

Touma recognized the creature before him because he had a vivid memory of the anime-original episodes in Naruto Shippuden.

That storyline had Naruto's team hired by the Land of Sea to protect a gold transport ship, leading to a series of events involving one of Orochimaru's secret research facilities in the Land of Sea.

The head of the facility, who had undergone human experimentation, possessed a spirit beast identical to the creature before Touma. It was called Umibozu.

Though Umibozu were rare in the Shinobi World, they weren't unheard of. Touma had come across plenty of descriptions of them in the ancient texts Orochimaru had collected.

To ordinary people, Umibozu were demons that lived in the sea and attacked ships. But to the ninja who had successfully captured one, they were gentle, almost entirely nonaggressive, and utterly useless summoning beasts.

Of course, it wasn't entirely fair to call them useless. Umibozu could regenerate naturally and use large-scale Water Release Ninjutsu. If controlled with a talisman, they could also be quite formidable in battle.

However, capturing and restraining an Umibozu was already difficult. Then there was the trouble of placing a talisman on the creature and training it to fight. In the eyes of efficiency-minded ninja, it simply wasn't worth the effort.

So even ninja who lived by the sea didn't target these unusual creatures. At most, they treated them as a pleasant pastime in their spare time.

This Umibozu had probably noticed the Natural Energy surrounding Touma and wanted to play with him.

However, as the water gently brushed over Touma's skin, he could feel a rich flow of Yang Release Chakra burrowing into his body.

Apparently, the Umibozu was trying to heal the injuries that the space-time teleportation had torn across his skin. It probably had no special medical skills and only knew how to inject Yang Release Chakra.

Touma formed a one-handed seal and used the Mystical Palm Technique, guiding the Umibozu's chakra with its Yang Release Chakra and helping it undergo a nature transformation.

Before long, the colorless chakra the Umibozu had released began to glow a faint yellow-green. That was the telltale sign of a nature transformation into Medical Ninjutsu chakra.

But this Yang Release nature transformation was still a little beyond the Umibozu's abilities. Touma could clearly see it shrink from a towering wall of water over ten meters tall to a fist-sized slime.

Its chakra was being depleted too quickly, and it didn't have enough to maintain its size. Shrinking reduced its consumption; it hadn't suffered any lasting harm.

The Umibozu's true core was inside its body. As long as Lightning Release or Fire Release didn't destroy it, the creature wouldn't die. It could convert Natural Energy into chakra and repair itself endlessly.

That's right. The way Umibozu obtained chakra was almost identical to the way Tailed Beasts did: both gained it by converting Natural Energy.

The only difference was that Tailed Beasts had such enormous chakra reserves that they could replenish what they used from Natural Energy before they ran out. They hardly ever had to worry about exhausting their chakra.

Umibozu, on the other hand, converted Natural Energy very slowly. After using up its chakra in a short time, it could hide away and wait for it to recover gradually.

Of course, if someone could help speed up its core from the outside, Umibozu could recover quickly. As it happened, Touma could do just that.

He used a Chakra Pill to replenish his own chakra, then entered Sage Mode for the second time.

This time, though, he didn't absorb all the Natural Energy gathering around him. Instead, he used some of his Senjutsu Chakra to create a vortex of Natural Energy in his palm.

When the vortex drew near, Touma clearly saw ripples of water appear across the Umibozu's tiny body, showing its excitement and delight. Under his gaze, it rapidly grew until it was nearly ten times its original height.

At that size, the amount of chakra the Umibozu's core could control had reached its limit. If it kept converting chakra by force, it would either be unable to grow any larger or its core would become overloaded.

Touma didn't push it. Instead, he took a red scroll from his ninja tool pouch and summoned a blue gourd from within it.

The gourd was a precious ninja tool Touma had picked up by chance. It was said to have been made by a clan in the Land of Water during the early Warring States period, modeled after the Six Paths Tool, the Amber Purifying Pot. It could hold a large volume of liquid.

It was called the Sea-Swallowing Gourd. The clan had developed it specifically for using Water Release Ninjutsu in unusually dry environments. Unfortunately, they never mass-produced it. Not long after making the prototype, the clan was wiped out in a major war.

Touma had picked up this prototype from a salvage team in the Land of Fire. They hadn't figured out how to activate its Cursed Seal, so they'd considered it little more than a worthless old relic. Touma had pieced together its history only after finding scattered descriptions of it in Orochimaru's collection of books.

He hadn't deciphered the corresponding Cursed Seal himself, though. He'd gone to Kushina Uzumaki, and the two of them had spent an afternoon experimenting until they worked it out.

If he'd had to experiment on his own, it probably would have taken years to discover the Cursed Seals needed to open and close it.

At first, he hadn't known what the thing was good for. He specialized in Wind, Lightning, and Fire Release, and was very unfamiliar with Water and Earth Release. He didn't drink much, either, so using it to store alcohol would have been a waste. He'd simply kept it sealed away in a scroll.

Now, though, it was a perfect match for Umibozu. Especially after he and the creature had formed a summoning contract, Umibozu hadn't found the space inside the Sea-Swallowing Gourd cramped at all. In fact, it had deliberately swept up a batch of fish, shrimp, and seaweed from the ocean floor to furnish its new home.

What had drawn Touma to Umibozu wasn't its affinity for Water Release. Rather, its still-undeveloped affinity for Yang Release could make it an excellent partner for Medical Ninjutsu, as long as it received proper guidance.

Touma remembered a complete medical Water Release inheritance from the Land of Wind among Orochimaru's ninja scrolls. The Second Kazekage, Shamon, had spent considerable effort developing it. After passing it down to his disciple, Chiyo, it gradually grew into one of the Shinobi World's two major medical systems.

That's right. The Shinobi World's two major medical systems were Konoha's Yang Release medical system and Sunagakure's Water Release medical system. The former had been developed by the Second Hokage, Senju Tobirama, based on the special constitution of the First, Senju Hashirama. The latter had been developed by the Second Kazekage, Shamon, based on the unique properties of the Loulan Medicinal Spring.

No other major or minor ninja village had developed a more advanced medical system. They had only the healing techniques passed down from the time of Ninshu and some basic surgical methods. That was the fundamental reason the other villages suffered such heavy losses in major wars!