Giritina form change

Just captured giritina, where can i acquire the griseous orb? And how can i change him to his primal form? I assume both the orb and primal form come later in the game?

To make it primal, give it a crystal piece. To get the grisious orb, it’s found later in the game in a location known as No Man’s Land.

Where can i acquire a crystal piece? The 2 i had were taken after i captured giritina.

Post game, after you defeat the timeless in the mew cave, the Burger King hands you some.