Now, I want to make it clear, I'm NOT writing this fic. I'm just giving this idea up for grabs. This is a One Piece crossover, involving on of Big Mom's most badass son.

After his loss against Luffy, something or someone, sends Katakuri to Equestruia. Upon waking up and finding himself in a land of horse people, he's also shocked to find he's 18 years old again. Also 85% of the country's population are female, but who's complaining. Anyhow, his intro would no doubt start rocky. What with the useless royal guard or Rainbow Dash picking a fight with anyone that looks "suspicious". But after saving the CMC's lives from anything from the Everfree, and the three cuties bonding with him, the mane 6 try to teach him the magic of friendship(much to his annoyance). Because despite his violet and intimidating personality and appearance, some ponies, specifically Pinkie, Twilight, Zecora, and the CMC, believe there's good in him.

Though despite finding them annoying, and the concept of "friendship is magic" to be ridiculous. Katakuri can't help but grow attached to the ponies, and see's them as a new family to protect. Which is easy considering that despite being 18, he's still as strong when back in his world. He especially becomes close to Pinkie after she makes him some extra large doughnuts, and starts seeing the CMC's as little sisters. Fluttershy on the other hand is terrified of his mouth and gaze, Rainbow doesn't trust anyone that's a better fighter then her, and Rarity despite fawning over his muscles would think of him as a brute.

Side note, if any of you were to give him a harem, which mare's would you all ship him with? My pick would be Pinkie, Twilight, Fluttershy, Rarity, Cheerilee, and Zecora.

So if anyone is interested, feel free to take this idea. As there aren't any stories here with Katakuri. My only request, is NO Displaced fics.

Personally I don't think he needs a harem at all if he went equestria

Dude can make donuts on a whim what makes you think Celestia wouldn't desire him?

I would think AJ and Pinkie would probably be very interested as he could probably create an obscene amount of desserts (and apple fritters, pies, turnovers and likely whatever else one can think up) quickly.