One Piece fans believe Luffy’s base form is on the level of a Yonko, but Kaido had already disproved this long before ...

Gear Five's white color may represent sunlight ... a faint white glow during the big battle against Kaido which is especially apparent when Luffy is pictured against the night sky.

Not every One Piece antagonist needs a deep flashback; Kaido's narrative sufficed to establish him as a compelling villain.

Not only did Luffy learn how to utilize the power of Ryuo, but, in the battle against Kaido, he went on to tap into the power of Supreme King Haki as well. To take things one step further ...