>>40499240I think X and Y is still part of the main universe, ORAS is the one in the alternate universe because the origin of mega stones is different between them. In XY they exist specifically in Kalos due to the ultimate weapon, and in ORAS they came from a meteor that Mega Rayquaza destroyed iirc. ORAS is also the first game to suggest the two universes as part of the plot involves scientists wanting to send an incoming meteor to another universe’s Hoenn so it’s no longer their own problem, and this Hoenn is implied to be the RSE one where mega evolution was never discovered
