He recycled Bullets backstory for him too. Odyssey is re-using a scrapped plotline for Shiki too.
I just rewatched Strong World, while not remembering anything about it.
It is WILD how much stuff from Strong World made it into Wano.
Floating island is final fight area? Check.
Bad guy wants to make a world full of powerful beings constantly fighting? Check.
Bad guy experiments on animals in weird ways? Check.
Bad guy's experiments causes drug reaction in impoverished civilians? Check.
Bad guy is having a giant party full of foreign pirates, and thinks the crew is already defeated? Check.
Small girl associated with illness who is tied to animals? Check.
Marines do nothing for no reason the entire time? Check.
The animals eventually turn on the bad guy? Check.
I could keep going on and on and on
No wonder so many people hated Wano, half of its plot points were already used in Strong World, in some cases better.
Shiki's plan was sooooooooooooooooooooooooooooooooo much better than Kaido's, too, it's hilarious