Kaido really is a hero, by enslaving the people of Wano he was able to make Joyboy return.
He really changed the world like he said he would.
Wano becomes a lot more interesting to me when you realize that Kaido's entire goal was to create the new Joy Boy. He wanted to be Joy Boy, realized he wasn't, and then dedicated his life to becoming everything Joy Boy stood against, the enemy of liberation.
Nika is what? A Mythical Zoan, with "Nika" meaning smile. After learning about Vegapunk cloning Zoan Fruits, Kaido tried to replicate this using Caesar, who knew of Vegapunk's science.
Kaido created a ton of artificial Zoans, because he wanted to replicate the Nika Fruit; this is why the artifical Zoan Fruits are called SMILES.
Kaido knew Joy Boy would liberate Wano, and start the world war with the World Government, so he built Joy Boy an army and created shit tons of weapons for him to use.
One of the craziest fail your way to success stories of all time; by becoming the ultimate villain, Kaido grew the ultimate hero, Joy Boy.