Seastone.
An ultra-rare mineral produced in only a handful of places in the world. It was like the crystallization of the sea, with a composition similar to seawater. It could even be called the sea in solid form, and it restrained Devil Fruit users even more effectively than the sea itself.
A Devil Fruit user would instantly lose all their strength upon touching high-purity Seastone. No matter how powerful they were, they would be helpless before Seastone.
And its ability to restrain Devil Fruit users was not its only trait. Seastone also possessed hardness far beyond that of ordinary materials. It was said to be harder than diamonds and far more resilient.
So even against those without Devil Fruit powers, Seastone handcuffs were often used for restraint.
Those two uses alone had made Seastone one of the most precious minerals in the world. After all, most powerful figures on the seas were Devil Fruit users, and Seastone, which could restrain them, was simply too important.
The problem was that Seastone production was far too scarce. The only place in the world with a stable Seastone output was Wano Country.
But it seemed that this situation was about to change?
Bright stared blankly at the unremarkable black stone on the table.
That was right. Wano Country could produce Seastone, but there was no reason it should be the only place in the world with Seastone mines, was there? Unless Seastone had been created because of Pluto.
There was naturally a good chance that veins of Seastone lay buried somewhere beneath the boundless sea. So why could one not be near Fish-Man Island?
This time, they had truly dug up treasure.
There was no way the place where they had found Seastone contained only this one piece, right?
"Bright, are you sure?"