Scions of the Storm

Instead of setting up a Stormcast Eternals unit on
the battlefield, you can place it to one side and
say that it is set up in the Celestial Realm as a
reserve unit.
You can set up 1 unit in the Celestial Realm for
each unit you have set up on the battlefield.
At the end of your movement phase, you can set
up 1 or more of the reserve units in the Celestial
Realm on the battlefield, more than 9" from all
enemy units.