15 years ago, in the secluded land of Wano within the New World, a martial arts master with white hair was teaching three kids; an upbeat purple haired kid, an uncaring red head and a serious green. "Kasai, Genkai, Senju, you three are the future of the Hanitsu D. name. Make your father proud!" He rushed all three of them, and swiftly beat their asses. "Failures! Work harder!"
He did this again the next day, not even letting them rest. He kept going at it for 12 years, before Genkai finally actually took him down. The master's hair was turning silver by this point, and age was getting to him. "So... fate has chosen you as the new master..." Genkai looked back at Kasai and Senju. "So, I guess we gotta keep going till one of you beat me." Senju looked down, and Kasai started shaking his head. "No way! We just did 10 years of that! You wanna keep going!?" He didn't answer him, Genkai just punched the wind out of Kasai and watched him fall. "Still too weak... If you want to give up, fine! Leave this place."
Kasai took that offer, and left the dojo he grew up in. He wandered Wano for a year, taking random jobs until he ended up as a cook in a ramen stall. Something about how he does it, everything he cooks just tastes heavenly, and he found he genuinely enjoyed it. One day, he found a fruit in the basket that looked odd. It was smile shaped with the stem coming from its center. It was really spiky, and he wasn't sure what it was. 'Maybe it's exotic?" He peeled the spikes away and bit into the flesh. It was pretty fruity. 'Mmm, could be better. Wyvern... wait what?' He suddenly began to shift, his whole body becoming scaley, and his arms shifted into wings. 'Oh shit! I'm a dragon!? Well, wyvern? Whatever! Wings!'
After about a month of practicing, he figured out how to properly fly, and decided it was time for a real test. "Alright... Anywhere but here! I need to see the world! Cook for more people! Let's gooo!" He sprinted towards a cliff, jumping off and shifting mod-air and started gliding, brushing the ocean with his tail. He let out an accomplished "WOO!!" as he began speeding up, trying to see just how fast he could go. He pushed mach 1, but wasn't quite there. After some flying he found a ship, and attempted to make contact.
"Well mister Ka-saw-e, we can bring you to the next town. Will that suffice?" He sighed, "It's Kasai, and yes. Anywhere is fine honestly." After some job hopping for years, Kasai ended up working as a cook in a cruise ship. He loved it, as that cruise traveled everywhere. Today, it was heading for Alabasta, a desert island. These fancy cruises got the same keels that let the navy pass through the Calm Belt. Before they even got that far, someone notified the captain of a kid on an island. They swooped by and picked him up, and continued on their way. Then the storm...
Kiwi, floating on a piece of debris, alive only because of his rubber body, could feel the water sapping his strength, and he was losing his grip on the wooden plank. Just before he did, Kasai scooped him out of the water and threw him onto his back. He flew around for a bit, but there were no more survivors. The only glimpse of hope was a nearby island, a place absolutely infested with huge bugs.