Nintendo launched a new Japanese trailer for Pokemon Sun and Moon. The trailer gives a preview of a large amount of gameplay. It also shows the new legendary pokémon, Solgaleo and Lunala.
You can also see someone who looks similar to Professor Oak on the trailer above at minute 1:31. It is revealed that he is Nariya Okido (Nariya Oak), Professor Oak’s cousin who lives in Alola region. Similar to his cousin, Nariya is also a professor. He studies Region Forms of Pokémon in Alola.