What do you do after you get 16 badges in pokemon soulsiver?

Answer 1

rebattle eleite four and champ then depending on the game go to paltriberg city??? (the one with brocks gym) by the poke center there is a man on a hill he will give you a wing (if its ss rainbow wing if its hg the clear wing) then you can get the other pokemon (ho-oh or lugia) by going to the bell tower or to the sea foam islands