Charlotte Katakuri is one of Luffy's many enemies, and is actually one of the strongest and most intimidating foes in the show. He is also a devil fruit user. He uses a logia type devil fruit called "Mochi Mochi no mi," or better said Mochi Mochi fruit. This fruit grants the user the ability to control mochi at free will. Though it is a weird thing to control, it is a lot stronger than you'd think. Adding on, one of the more weird features about Katakuri is his jaw. When katakuri was a child, he loved eating food, specifically donuts. He ate them so much his jaw became dislocated forcing him to cover his face with a ragged scarf, therefore making him look even more intimidating. The actual fight between Luffy and Katakuri was one of the best fight in the entire series. He is overall a great character and in my opinion the one of the villians in the show.