Kalos Starters, Xerneas, Yveltal, Zygarde and Zeraora all get new megas. All types stay the same except Xerneas becomes Fairy/Grass and Zeraora become Electric/Fighting. There's more megas but I'd like those to be a surprise.

Lumiose City is almost as big as Paldea. It is split into multiple sections. Prism Tower, the outskirts are split into three, and the Catacombs, which have a few different biomes.

New 4th Legendary based on Odin. It's the main antagonist of the game. The Z-A in the title represents the beginning of a cycle. The Odin legend wishes to reset the universe and Zygarde won't let it.

Set shortly after Paldea.