September marks the start of Pokemon Go 's latest season, Twilight Trails, and the mobile game is ushering it in with a number of events and Pokemon debuts this month.  A host of Mega Pokemon are returning once more as part of the Mega Ascension event, which will lead into the big Go Fest Mega Finale on September 5-6. Later in the month, the dark-type Pokemon Maschiff and Mabosstiff will make their debut, and a new Mega-Evolved Pokemon will star in another Super Mega Raid Day. On top of that, players can look forward to new Raid bosses and Spotlight Pokemon this month, as well as a…