[Original Fruit + Not a mindless power fantasy] On his third day after transmigrating to the world of One Piece, Lin Bei was cornered on a beach by pirates. He had planned to stick to his principle that “Devil Fruits are so disgusting even a dog wouldn’t eat one,” but to stay alive, he tearfully swallowed an unknown fruit that tasted like shit: the Gravel Fruit. It could devour matter to grow infinitely stronger, and even swallow iron, water, and Seastone? Damn, what was he waiting for? Starting from an unknown island in the East Blue, he was going to devour the entire sea!
The Devil Fruit setting in this fanfiction is its biggest highlight. It retains the properties of the consumed matter: consuming iron grants iron-like hardness, consuming bones grants bone toughness, resulting in a very rich growth path. It's not mindless overpowered power; the cyclical logic of physical limits → training → feedback is self-consistent.