User blog comment:Kaido King of the Beasts/Chapter 784 Prediction: Gear Fourth/@comment-4849407-20150422024056/@comment-176.145.198.155-20150422191335

That wouldn't and I'm pretty sure Strong World was said to be canon as Oda writed the story himself. By the way, he didn't for film Z. He just looked at their work and did some change himself (like Kuzan as he didn't appear in the manga at that moment but still had the same design). 3D2Y is not made by Oda too. People believe it's canon because they can't accept the fact that Luffy came up with a move like red hawk or Gear 2nd by himself.