Card Rulings:March of the Monarchs

OCG Rulings

 * The "Tribute Summoned monsters you control cannot be targeted by, or destroyed by, card effects." effect of "March of the Monarchs" is also applied to monsters that have been Tribute Set or that have been Tribute Summoned and later flipped face-down. Therefore, if "Dark Hole" is activated, the monsters that have been Tribute Set or that have been Tribute Summoned and later flipped face-down are not destroyed.