In East Asian folklore, Chinese style dragons (like Kaido) may often represent good fortune. Whether Kaido is a dragon that ate a human fruit as some theorize or, much more likely, a human who ate a mythical zoan, I believe his power bestows upon him incredible good fortune in battle. If there is a remote chance, diving from a sky island, that one can collide with the Earth and survive, that a rope will snap or a guillotine will crack in an attempted execution, the odds are always in Kaido’s favor.
Interestingly, I think we were given a hint by Oda during Kaido’s introduction that this is the case. The narration box reads, ‘In a one on one fight, always bet on Kaido.’ The Beast Pirates and the upper echelon of the subsidiary Donquixote Family have names themed after card games or, in other words, games of chance. Basil Hawkins decided to join Kaido when he recognized the odds were overwhelmingly in Kaido’s favor.
It’s worth noting that Momonosuke has a ‘special’ artificial Zoan which seems to be very similar to that of Kaido’s. If, in addition to its transformative power, the artificial Dragon fruit imbues Momo with the same good fortune that has kept Kaido alive for all these years, Momo could be the key to finally ending Kaido’s winning streak.
We actually have reason to believe that Mythical Zoan are not simple transformation powers like regular Zoan fruit. Marco’s phoenix flames have a healing, restorative property, matching the fabled powers of a phoenix in real world myths and folklore. It thus would make sense for a mythical Dragon fruit to grant its users additional powers which correlate to real world folklore.
Kaido, specifically, is themed on an Eastern style Dragon as is, seemingly, Momonosuke. To lend a bit more weight to this theory, there may be evidence that Momo has also been imbued with good fortune. Luffy discovers Momo in the scrap heap on Punk Hazard just before Momo succumbs to starvation. Similarly, the Scabbards arrive on the scene at the exact moment Momo is to be executed by Kaido, thus sparing his life.
Kaido’s introduction into the story is accompanied with narration boxes describing forty failed attempts at capital punishment. Thus, Momo’s survival may parallel Kaido’s providing further evidence that Wano’s future Shogun may be the true key to its liberation.
*Theory by Straw Hat Jedi