If Tony had known a little more, spent less time cutting people down and more time reading, he would have recognized what Jones's swollen right arm had become: a turtle shell.
There was an island on this sea covered in Volcanoes and towering, badly weathered Stones. Because it lay at the edge of the Red Line's tectonic plate, volcanic eruptions and major earthquakes struck often. Whenever they did, countless pebbles and boulders rained down on every living creature.
It sounded absurd, but this was the One Piece World. Anything was possible.
Under those brutal conditions, one group of creatures after another had gone extinct. Coarse sand and gravel dominated the island, where not a speck of green appeared all year.
Only a population of sea turtles had survived and multiplied. Their numbers had even kept growing.
With so many Volcanoes and lava pits across the island, they had been named Lava Turtles.
From the moment they hatched, these Lava Turtles spent their lives getting pelted with things. It was a miserable existence. By the principles of Darwin's Theory of Evolution—assuming they even applied this far from Earth—the turtles gradually developed astonishing toughness to adapt. An adult Lava Turtle could take a one-ton boulder falling from hundreds of meters up without injury!
They were terrifyingly tough inside and out!
What made that incredible feat possible was the thick Turtle Shell they were born with. Not only was it as hard as Seastone, but its unique internal structure greatly reduced the force transmitted into the turtle's body when struck. Apart from its weight, it was the perfect material for a shield!
It was a strategic resource sought after by many factions and used to forge components for large machines.
Back when Jones was still the boss of Kuriswia, he could not leave,