ZD DEATH FROM THE SKIES TRAIT

Death From The Skies
Instead of setting up this model on the battlefield
you can place it to one side and say that it is
soaring in the skies in reserve. If you do so, at
the end of your first movement phase, you must
set up this unit on the battlefield more than 9"
from any enemy units.
(This steed soars above its master’s army,
before swooping to attack)