The bird dudes we’ve seen in BotW were confirmed to be Rito, which as far as we know are only in Adult, plus the Koroks and the Deku Tree are back. The problem that everybody is freaking out about is that there’s also Zora in the game, and those evolved into Rito. I’m guessing that somebody somehow rejoined the two worlds (since that’s essentially what they are), perhaps even causing Calamity Ganon to wreak havoc.
