If God Emperor Doom is blocked by 4 or more character dice, return the blocked die to its card.
When does this effect actually occur? Does it happen immediately after all blockers are declared or is it at the end of the attack step after damage is dealt (assuming he would return to his card regardless of if he survived or not)?
If the former, I presume that would mean that the dice blocking him are still spoken for and cannot switch to block a different die.
If it's the latter, could you theoretically use some ability during the global window that spins/rerolls him to an energy face and save him from having to go back to his card (since he would technically no longer be on the field and thus not actually blocked anymore)?