Kachi Kachi no Mi

Introduced in the film Clockwork Island Adventure, this non-canon Paramecia power grants its eater the ability to stiffen and warm the body at will. The name toys with kachikachi, a Japanese onomatopoeia that covers both stones struck together to spark a flame and the noise of something turning hard, each pointing to one of the fruit's two effects. Its BStation release goes by the Hard-Hard Fruit. The lone eater is Bear King, a member of the Trump Siblings.

The power hardens the user's body to raise their defense, producing a shell so sturdy that even the boring force of the King Cannon failed to punch through; in the end a collapsing floor, not a direct hit, brought Bear King down. He can additionally heat his hardened parts, boosting their striking power and igniting things on contact, as his chair discovered. No particular vulnerability shows up beyond the standard Devil Fruit weaknesses. Its single named move, Hot Boiling Special, sees him warm his fist before driving it into an opponent.

Bear King alone has eaten the fruit. He stiffens himself to weather attacks and to hit with more force, and the extra heat lets him burn whatever he lays hands on. The power joins a short roster of heat-producing abilities in the series: the Netsu Netsu no Mi belongs to that group, as do the Gutsu Gutsu no Mi, the Bana Bana no Mi, and the Atsu Atsu no Mi. Its body-hardening quality, meanwhile, brings two other things to mind: the Kira Kira no Mi, plus the defensive coating of Armament Haki. Tellingly, the fruit surfaces in only one line of dialogue, which the Manga Entertainment dub rewrote to strip away any mention of it.