King's sword > Kaido's club.
There is a reason Kaido doesn't use club to strike Orochi but instead borrowing King's sword.
Just as I told you, all out King with his hybrid and sword > Dragon Kaido with his Borobreath that won't damage King badly because it's fire elemental.
Meanwhile King with his stronger-than-Kaido's-club sword will slice and dice the dragon's giant body with his advanced CoA that ignores target's durability.
Hybrid Kaido > Base Kaido ~ King > dragon Kaido.