Kaido said this but at the end of the day he is as strong as he is because of a Devil Fruit and he literally believes Joyboy who is a DF user is the only capable of beating him and both user their fruit powers as the ultimate attack…
Now Kaido also had no idea of the existence of Imu and the Gorosei’s true nature… As the series comes to a close we will really see the Devil in Devil Fruit.
Yami the most evil of them all. Nika the most ridiculous. The only two that peak the interest of Imu…