The Stage is Set
(Rule)Description: Before the start of the first turn, when placing units into Reserves, if Fulgrim Transfigured has not joined a unit and does not have a Retinue Squad, the controlling player may place Fulgrim Transfigured into Reserves and must declare to their opponent a Turn number from Turn 2 - 4, indicating on which of their own turns they will bring Fulgrim Transfigured into play from Reserves. At the start of the declared turn, the controlling player must place Fulgrim Transfigured wholly within 6" of a unit with the Legiones Hereticus (Emperor’s Children) special rule, and not within 1" of any enemy models. If this is not possible, Fulgrim Transfigured cannot be set up this turn, and the controlling player must attempt to deploy Fulgrim Transfigured again at the start of their following turn.
Until Fulgrim Transfigured is placed on the battlefield in this manner, all models in a Detachment he is part of have the Stubborn special rule.