Oguro followed the records from the original work and tried communicating with his Zanpakutō.
Unfortunately, there was no sign of Bankai at all.
Normally, achieving Bankai required first materializing the Zanpakutō, then forcing it into submission.
But Oguro's Zanpakutō had no possibility of materialization.
Because his Zanpakutō could transform into any Zanpakutō, it had no fixed form.
And without a fixed form, materialization was naturally impossible.
Which meant making it submit was even more out of the question.
"So… does that mean I can't use Bankai at all?"
With no other choice, Oguro threw the problem to the system.
He trusted that the all-powerful system would give him an answer.
And the system didn't disappoint.
Although Oguro's Zanpakutō spirit had no fixed form, it could transform into the form of other Zanpakutō.
As long as Oguro could force the Zanpakutō in that transformed state to submit, he would be able to master that specific Bankai.
"Hiss… so that means every single Bankai has to be trained separately? That's insanely troublesome."
Just the Bankai Oguro remembered off the top of his head already numbered over twenty.
The system then provided a shortcut.
He could directly copy a Bankai from its original owner using achievement points.
The only issue was the price.
From one hundred thousand to over a million.
Soifon's Bankai, Jakuho Raikōben, cost two hundred thousand.
Byakuya Kuchiki's Senbonzakura Kageyoshi cost a staggering three hundred thousand.
Oguro even curiously checked the Captain-Commander Yamamoto Genryūsai Shigekuni's Bankai.
That long string of zeros instantly killed any desire he had to count further.
Alright then.
Just when he thought life was getting easier, achievement points were still nowhere near enough.
Fortunately, with captain-level strength now, there was no need to rush.
One day, Oguro was leisurely fishing on the ship when Rukia brought him a newspaper.
Oguro glanced at it.
It was Luffy.
After lying low for a while, just like in the original timeline, Luffy had gone to Marineford again to leave a message for his companions.
Only this time, the one accompanying him wasn't Rayleigh.
It was Emporio Ivankov… and Sabo.
Looking at the young man wearing a top hat, Oguro finally understood where Kuma had sent Luffy.
Straight to his old man.
With Sabo, a near-admiral-level powerhouse, providing escort, Marineford with its upper ranks absent was naturally helpless.
The two-year promise still stood, but this time the meeting place wasn't Sabaody Archipelago.
After all, their new ship was still being built at Water 7.
Another thing worth mentioning was the Going Merry.
Oguro had salvaged it.
When the Straw Hats were all sent flying by Kuma, the Merry had been left behind with no one to care for her.
Oguro couldn't bear to see a ship with a ship spirit vanish like that, so he brought her back using the World Crossing Gate.
The ship spirit was overjoyed and thanked Oguro.
But she still gently refused his offer.
Oguro felt a bit regretful, but didn't force the loyal little spirit.
After drifting peacefully at sea for a few days, Oguro suddenly received a call for help.
"Oguro, it's Ace."
Ace, who was now the acting captain of the Whitebeard Pirates.
The reason he was only acting captain was simple.
First, no one could accept anyone other than Whitebeard as captain.
Second, Ace's strength wasn't enough yet. He couldn't carry the title of a Yonko.
"Ace, what's going on?" Oguro asked.
"I wanted to ask you about what you said before… about flame temperature."
Ace sounded urgent.
"Teach is aggressively taking over Pops' territory right now. I've fought him twice, and I couldn't do anything to him."
"And his subordinates are strong too. We've already lost far too much territory."
"I have to get stronger, fast. Otherwise… I can't face Pops in death."
Ace's voice dropped, carrying a trace of despair.
In the recent clashes with Teach, the Whitebeard Pirates had suffered heavy losses.
Even several allied crew captains had died.
If it weren't for Marco holding things together, even division commanders might have fallen.
There was no helping it.
The Dark-Dark Fruit was simply too oppressive against Devil Fruit users.
Oguro felt a bit helpless after hearing this.
Flame temperature was easy to understand for someone who had studied physics.
But in the One Piece world, where illiteracy was everywhere, he was absolutely sure Ace wouldn't get it.
After thinking for a moment, Oguro said,
"If you want to raise the temperature of your flames, then compared to the scale of the fire, what really matters is the structure inside the flame."
"To put it simply, it's like the difference between an army of a hundred ordinary people and an army of a hundred Whitebeards."
Ace pondered for a moment. "The inside, huh… I've honestly never thought about that."
Oguro thought it over, then decided to go all the way.
"Ace, just talking probably won't give you a real feel for it. You should find a flame with truly extreme heat and experience it yourself."
"You ate the Flame-Flame Fruit. You should be able to sense the internal differences between flames."
Ace froze, then hesitated. "Higher temperature flames? You want me to find magma?"
With Ace's experience, magma was about the only thing hotter than his flames.
Oguro rolled his eyes.
Magma?
How unambitious can you be?
I'm planning for you to burn a certain magma man to ash someday.
And you want to learn magma instead?
"Forget it. I'll tell you something. Write this down. This thing burns way hotter than your flames. It'll be more than enough for you to study."
After thinking briefly, Oguro began reciting a formula.
"Grind high-purity aluminum bars and hematite into powder. Mix them in a ratio of 100 to 295, then ignite it."
"As for the temperature, it's not that high. Around two thousand five hundred degrees Celsius."
"Pfft—what?! How much?!"
Ace's voice shot up in shock.
Magma only reached around fourteen hundred degrees.
This was over a thousand degrees higher.
Oguro snorted. "Tch. That's enough to scare you? If you had the conditions, I could even get you four or five thousand degrees."
The formula Oguro gave was simply thermite, extremely common in his previous life and often used for welding.
During wartime, it was even made into grenades to burn through tank armor.
Nothing special at all.
If he had access to a high-energy electron furnace, four or five thousand degrees would be trivial.
Ace was already half numb from shock.
He didn't dare dream about four or five thousand degrees.
Two thousand five hundred was already more than enough.
Once he figured it out, he had to grab Akainu by the head and ask him who the superior fruit really belonged to.
After thanking Oguro, Ace hung up the Den Den Mushi and rushed off to prepare the thermite.
At that moment, Oguro suddenly remembered something.
Blackbeard was seizing Whitebeard's territories.
Which meant Fish-Man Island had lost Whitebeard's protection.
That place…
Absolutely could not be handed over to Big Mom.