At that moment, Oguro suddenly remembered something.
Didn't Fish-Man Island have a Poneglyph?
Maybe Robin could come take a look.
Of course, the Poneglyph was one of Fish-Man Island's national treasures, so they would need King Neptune's permission first.
After Oguro mentioned it to Jinbe, Jinbe didn't dare make the decision on his own and could only go report it to Neptune.
Oguro didn't mind at all.
In his view, Neptune would most likely agree.
After all, the Poneglyph didn't have much practical value for Fish-Man Island itself.
While waiting for Jinbe to return, Shyarly led the group to a nearby pavilion to sit down.
Merfolk gradually gathered around them, curiously watching the humans who had arrived. Instead, it formed a vivid and dazzling scene of different styles and colors, like flowers in full bloom.
Oguro took a sip of the drink sold in the bay. It was sweet and sour, perfectly refreshing.
He glanced at Shyarly and slowly spoke.
"Madam Shyarly, there's something I need to tell you."
"Your brother, Arlong, is dead. I killed him."
The scene instantly fell silent.
Nami's eyes widened in shock.
That Arlong… the one who had oppressed her hometown… was actually Madam Shyarly's brother?
She looked at Oguro with concern.
This was a blood feud.
She could only hope Madam Shyarly would stay rational.
If she tried to seek revenge, the consequences didn't even need to be imagined. Fish-Man Island itself might end up suffering badly.
What eased Nami's worries was that Shyarly showed neither overwhelming grief nor deep hatred.
Instead, there was a look of "as expected" on her face.
She slowly spoke.
"When Arlong left home back then, I already guessed this would be the ending."
Nami's mouth twitched.
She just… accepted it like that?
Shyarly continued calmly.
"Arlong's ideology was far too dangerous. He preached fish-men supremacy, but never considered this."
"If that were really true, how could we have been trapped on Fish-Man Island for hundreds of years?"
"Once he went to the surface, it was only a matter of time before he provoked someone he shouldn't have. This outcome was inevitable."
Oguro clicked his tongue inwardly.
No wonder she was someone who could foresee the future. She accepted certain things frighteningly fast.
Of course, there was also an important reason behind it.
The relationship between Shyarly and Arlong had always been distant.
Their beliefs were completely opposed.
Shyarly had long despised the violent culture of Fish-Man District.
That was why, after growing up, she moved to Coral Hill where merfolk lived and completely cut ties with Arlong.
They were blood relatives, but their bond was barely stronger than that of strangers.
"If the people in Fish-Man District understood this, Fish-Man Island wouldn't be plagued by so much rot," Oguro said with a sigh.
Once Fish-Man Island came under his control, Fish-Man District would definitely be demolished.
And if anyone dared to resist, he would make those fish-men understand exactly why they had been forced to crawl in the gutters all this time.
Not long after, Jinbe returned.
Just as Oguro had expected, Neptune agreed to let Oguro view the Poneglyph.
In fact, it would be more accurate to say Neptune was eager for them to go.
The location of the Poneglyph was deep within Fish-Man Island, extremely far from the port.
Neptune instructed Jinbe to delay them as much as possible.
If they could stall there until the Big Mom Pirates left, that would be ideal.
The Sea Forest… a remote forest area of Fish-Man Island rarely visited by anyone.
Originally, two Poneglyphs were placed there.
One was Joy Boy's apology letter.
The other recorded the coordinates of the final island, Laugh Tale.
Unfortunately, only Joy Boy's apology letter remained now.
Oguro asked Jinbe about the whereabouts of the red Poneglyph, but Jinbe didn't know either.
According to rumors, it had simply disappeared one day.
Since there were no guards stationed in the Sea Forest, someone could have stolen it without anyone noticing.
Oguro didn't really care.
After all, he had little interest in the so-called final island.
He opened the Senkaimon gate, and Robin stepped out from the other side.
Knowing there was a Poneglyph here, she was beyond excited.
But the moment the gate appeared, both Jinbe and Shyarly were stunned.
What kind of Devil Fruit ability was this?
It could transport people directly from the surface to the deep sea?
If someone used this power to attack Fish-Man Island, then the island's natural defense of being tens of thousands of meters underwater would be completely meaningless.
Seeing their reactions, Oguro smiled and reassured them.
"Don't worry. This is a power exclusively controlled by our Sacred Holy Spirit Empire."
"And without the host's permission, we wouldn't casually enter someone else's territory."
With Oguro's assurance, Jinbe finally relaxed a little.
If someone used such an ability openly in front of you, then they clearly didn't harbor ill intent.
Before long, Robin finished deciphering the Poneglyph.
It was indeed Joy Boy's apology letter.
Filled with apologies, regrets, and sorrowful words… yet it contained almost no useful information.
She turned to the group and said,
"This is an apology letter signed by Joy Boy. But the contents are very vague. It doesn't explain who he really was, or why he was apologizing."
"Joy Boy? An apology?"
Jinbe and Shyarly blinked, completely confused.
Even the people of Fish-Man Island themselves knew very little about this history.
Oguro shrugged and casually explained.
"It's simple. Joy Boy promised to bring Fish-Man Island back to the surface, but failed… so he wrote this apology letter."
"How do you know that?"
Robin was shocked.
The Poneglyph was extremely vague about what happened back then. It never stated that clearly.
Once again, she felt just how deep Oguro's understanding of the world truly was.
Even the scholars of Ohara would probably pale in comparison.
"Returning to the surface… that's easier said than done," Jinbe said, shaking his head. He clearly didn't take Joy Boy's promise seriously.
Oguro shook his head in response.
"No. Back then was actually Fish-Man Island's best chance to return to the surface."
"And that chance was ruined by Joy Boy himself."
"What?"
Both Jinbe and Shyarly were utterly shocked.
Wasn't Joy Boy apologizing because he failed to keep his promise?
How did it turn into him destroying Fish-Man Island's opportunity?
Oguro thought for a moment. These two weren't outsiders, so there was no harm in telling them.
"The reason Joy Boy made that promise with the Mermaid Princess back then…"
"…was because the Mermaid Princess of that era possessed a power capable of overturning the world."
Oguro looked at them, speaking each word clearly.
"One of the Three Ancient Weapons."
"Poseidon, the Sea King."
Poseidon… actually belonged to Fish-Man Island?
The revelation hit Jinbe and Shyarly like a thunderbolt.
And then Oguro dropped an even heavier bombshell.
"Because of Pluton and Uranus, people assume Poseidon is also a weapon."
"But in reality, Poseidon is the Mermaid Princess herself."
"Because she can command the Sea Kings."
"And Joy Boy's so-called promise to help her…"
"…was actually a shackle placed upon her."