shelgon:

A new release of information has come for Pokémon Sun & Moon. We’re currently compiling all the information from the trailer so keep checking back
Rowlet’s evolution is called Decidueye which is Grass/Ghost. It has the move Spirit Shackle that prevents opponents switching out. Litten’s evolution is Incineroar with the move Darkest Lariat which ignores stat changes. It is Fire/Dark. Popplio’s is called Primaria and is Water/Fairy
The island guardians are Tapu Lele which is Psychic/Fairy with the ability Psychic Surge. Tapu Bulu which is Grass/Fairy with Grassy Surge and Tapu Mini which is Water/Fairy with Water Surge. Each of these set their respective Terrains. They have their unique Z-Move, Guardian of Alola.
A new Pokémon is revealed called Cosmog. It is Psychic-type with the ability Unaware.
Persian is pure Dark-type with the abilities Fur Coat and Technician
In the game, they are trying to create a league and the champions of the league take on the Battle Tree where trainers like Cynthia, Blue and Red are

Source: Serebii | English Trailer | Japanese Trailer