After both Groudon and Kyogre have been awakened, go to Sootopolis city and talk to steven, who will take you to the cave of origin. Find Wallace and he will unlock it.
There is Only a Sky Pillar
the sky pillar is in pacfidlog town
sky pillar on the sky pillar on rt 114
Sky Pillar is located toward the northern edge of Route 131. As you surf across the water, just find a path that leads upwards to Sky Pillar.
go to the sky pillar
in the sky pillar
say hi
It is it the top of Sky Pillar
Its raquaza. u can get him at sky pillar.
sky pillar or evolve a duskull
At the sky pillar by pacificlog town
you cant you can only get to it on Pokemon emerald