Literature
My Full Pokemon Sun and Moon Theory
Full of Rare Pokemon
This is something Professor Kukui says in one of the trailers for Pokemon Sun and Moon. Now I believe he says that for a reason, and that reason is in these games there will be more Legendary/Mythical pokemon integral to the story than in any other games before it. Not only are there Solgaleo and Lunala, but Zygarde, Magearna, Volcanion AND the un-named Eclipse pokemon (most speculate to be named Marshadow, to which I agree). Remember that this is the game where "It all comes together."
Magearna and Volcanion...what?
Yes. I do believe that these two will be in Alola AND an integral part of the story. From the Magearna m