After having a phone call with Rosinante, Tanaka did not return to the Naruto world. Instead, he cut off another three pounds of Sea King meat and continued roasting it over the fire.
Through his previous training, he roughly estimated that with his current physical fitness, combined with chakra molding, taijutsu training, or the development of the Op-Op Fruit, he could fully digest and absorb about three pounds of Sea King meat within two hours.
In other words, the nutrients from three pounds of Sea King meat could sustain him for two hours of training.
During this period, it was as if he had activated a double experience buff—whether it was molding chakra, practicing taijutsu, or developing the Op-Op Fruit, everything was twice as effective.
His improvement speed was at least twice as fast as it was in the Naruto world.
And there were no side effects.
Because of this, Tanaka was in no rush to return to the Naruto world.
After all, he was the heir of the Hyūga clan. Unless it was a major event that concerned the rise or fall of the clan, all the clan's affairs were handled by Hizashi and the other Hyūga elders.
His only tasks were to train and eat; train and eat; train some more and eat again.
After finishing the three pounds of roasted Sea King meat, he took a short break before getting up, holding his sword, activating ROOM, and continuing to develop his Devil Fruit abilities.
To strengthen and enhance the power of a Devil Fruit, there were three key aspects:
Improving the user's own strength—this included taijutsu, swordsmanship, Haki, and even chakra training.
Relentless training—using and molding the fruit's abilities every single day, year after year.
And creativity—understanding the Devil Fruit deeply and developing unique techniques.
Take the Brain-Brain Fruit, for example. If a monkey were to eat it, at best, the monkey might evolve into Super Saiyan 1. But if Vegapunk ate it, he would immediately achieve Super Saiyan God, leading the world by 500 years.
While others were still playing with firearms, he was already using laser guns.
While others spent their entire lives relying on a single Devil Fruit, he was creating artificial Devil Fruits—specifically, Mythical Zoans.
While others became stronger through mutations, training, or battles, he was mass-producing Pacifistas, Seraphim, and even creating the Mother Flame.
Tanaka, though not a doctor and lacking medical expertise, knew how to copy others' work.
At this early stage, copying Law's development path was the safest bet.
Once he had completed the foundational development of the Op-Op Fruit and reached a certain level of strength, he would integrate his own understanding and methods.
For example, combining the Op-Op Fruit with the Byakugan, Gentle Fist, and chakra.
Or applying a new idea that had suddenly come to him—using the Op-Op Fruit's power to merge the bloodline factors and bloodline limits of both the Naruto and One Piece worlds.
Over the next two hours, he continuously trained his Devil Fruit abilities.
Once he had exhausted his stamina, he would sit down to rest.
Since the Sea King meat he consumed allowed him to recover quickly, he could resume using the Op-Op Fruit shortly after.
After two hours, he cut another three pounds of Sea King meat, roasted it, and ate it.
After resting for a bit, he activated his Byakugan, assumed the starting stance for Gentle Fist, and began practicing the Hyūga clan's advanced taijutsu techniques.
This included the Gentle Step Twin Lion Fists, which involved chakra shape transformation.
In this process, he not only learned new techniques but also trained his body.
A perfect two-in-one benefit.
And so, most of the day quietly passed in training.
After going through chakra molding, Devil Fruit training, and taijutsu practice, Tanaka reflected on his progress.
By consuming Sea King meat and then training, he achieved more in half a day than he would have in two full days of training in the Naruto world.
Especially when it came to chakra—it was growing at an astonishing rate.
Thinking about this, Tanaka turned his gaze toward the nearby Sea King.
After half a day of training, he had only eaten about ten pounds of meat.
Considering that the Sea King was over 70 meters long, this was equivalent to a regular person cutting off a fingernail-sized piece of skin—if not even less.
Furthermore, since he had been cutting meat from the Sea King's tail, with the creature's immense vitality, it would fully regenerate in a few days if thrown back into the sea.
"How should I deal with this?"
Looking at the massive Sea King in front of him, he frowned slightly, wondering how best to handle it.
With his current appetite and digestion rate, ten pounds of meat per day was his limit.
Eating more wouldn't be useful, his body wouldn't be able to process it efficiently and would only place extra strain on his organs.
Besides, he couldn't train non-stop forever. Even if his body could handle it, his mind would eventually become exhausted.
A 70-meter-long, thousand-ton Sea King—eating just a bit of its meat and letting it go would be a waste, but killing it outright would be excessive.
After all, this was only the North Blue, not the Grand Line, not the New World, and certainly not the windless zone filled with Sea Kings.
Whether he killed it or let it go, there was no guarantee that he'd be able to lure in another Sea King next time.
He might only end up attracting a mere sea beast instead.
"I've got it."
After a brief moment of thought, Tanaka came up with a name.
Tenten.
A woman who could seal the ocean into a scroll and summon it at will.
A woman who carried a billion kunai with explosive tags.
A woman who could summon a massive ship from a scroll.
When it came to space-time ninjutsu for storage and summoning weapons, he probably wasn't on the same level as Tenten. But if talent wasn't enough, then quantity would make up for it.
If he couldn't be like her, who could store an entire ocean in a palm-sized scroll... Then he'd just use ten scrolls instead.
With a plan in mind, he opened the Void Walker's Gate and returned to the Naruto world in an instant.
A short while later, he reappeared in the One Piece world at the exact spot he had left. This time, however, he carried a backpack full of scrolls.
As the Hyūga clan's heir, getting a single backpack of scrolls was nothing. If he wanted, someone would immediately bring him an entire cartload of them.
When it came to money... After the Senju clan was confiscated and nationalized, only three ninja clans remained the wealthiest in Konoha.
One was the Hyūga clan.
Another was the Uchiha clan.
The last one, and the richest, was the Sarutobi clan.
Especially during the current era of Konoha, the Sarutobi clan was not only the largest in the ninja world but also the wealthiest.
Even now, after taking half of the Senju's assets and leeching off Konoha for years, the Sarutobi clan remained the most powerful family in the village.
"Amputate."
Tanaka expanded his ROOM, covering the Sea King. Then, with a single precise cut, he ended its life swiftly and painlessly—an act of mercy.
After that, he delivered several consecutive slashes, slicing the enormous creature into pieces.
Each chunk of Sea King meat was the size of an adult grizzly bear.
Next, he sealed each piece into separate scrolls.
In fact, aside from cutting up the Sea King and storing it in scrolls, he had considered another method.
Summoning Jutsu.
If he signed a contract with the Sea King, he could simply release it back into the ocean. Whenever he needed, he could summon it to the One Piece world using Summoning Jutsu.
Compared to sealing it in scrolls, summoning it whenever needed would be a much simpler and more direct solution.
However, Tanaka ultimately abandoned the idea.
Killing, but not torturing.
This wasn't hypocrisy.
Just as humans needed to eat meat to survive, Sea Kings also needed to hunt other species, even their own kind, to live.
Survival of the fittest. The law of the jungle.
There was nothing more to it.
If he wanted to survive in the brutal Naruto world... If he wanted to thrive in the merciless One Piece world and stand at the pinnacle of both...
Then he had to make Sea Kings his food source.
But if he used Summoning Jutsu to call the same Sea King over and over—each time cutting off a portion of its flesh before letting it go...
Repeating this endlessly, again and again, until it had lost too much and could no longer regenerate... Until it was eaten alive, piece by piece...
That was simply too cruel.
So, he chose to give it a swift, painless death and seal its remains in storage scrolls.
Even if this method was more troublesome and required extra effort, he preferred it over summoning and repeatedly butchering the same creature.
At least this way, he could have peace of mind.