Hey guys I'm here to leak new info about USUM.

The "mysterious strangers" at the top of a certain promo poster are the following characters:

Faba
Wicke
Jupiter (from Galactic)
Stoeptegel (new character)

They're trying to rescue Cyrus from Destortion World, but they need the power from the strongest UBs.
Necrozma and Solgaleo/Lunala.

Also you can travel through the entirety of Sinnoh in the post game.