Ultimate Great Spell, World Pandemic!/Rulings

Japanese FAQ Rulings (Source)

 * Q2185: What happens when a flag is turned face down?
 * A: Because the abilities written on the flag are lost, you cannot use the specified cards. All cards on the field that are now unusable are placed in the Drop Zone. Also, you cannot call, equip, or cast a card that you cannot use from your hand.


 * Q2186: When my flag is turned face down, can I use the Soulguard of the card that is being sent to the Drop Zone?
 * A: No, you cannot. Cards that cannot be used lose all information, such as their abilities.


 * Q2187: If my flag is turned face down, can I use  cards?
 * A: No, you cannot. You cannot use it because the ability " cards can be used" is lost from the flag.


 * Q2188: If my flag is turned face down, can I use Omni Lord cards?
 * A: Yes, you can. Just like cards with "use with all flags", you can use Omni Lord cards even with a face down flag.


 * Q2189: Can cards in my Drop Zone use their abilities if my flag is turned face down?
 * A: No, you cannot. If your flag is flipped, the cards in your Drop Zone lose all information, including their abilities.


 * Q2190: In response to the casting of this card, my opponent cast Chillax!. During that turn, if my opponent is damaged, will the damage be reduced to 0 and that player will gain 1 life by the effect of Chillax!?
 * A: Yes, they will. Even if the flag is turned face down, the effect of a card that has already resolved will still be active.


 * Q2191: If my life becomes 0 while I have my Dragon Zwei flag turned face down, can I play Dragon Drei from my hand on top of my flag?
 * A: No, you cannot. If the flag is turned face down, the name of Dragon Zwei is lost, so you cannot play Dragon Drei from your hand on top of your flag.


 * Q2192: If my buddy is Fake Replica Weapon, Gemclone, and my Hero World flag is turned face down, can I use Impact Monsters other than Hero World?
 * A: No, you cannot.


 * Q2193: I am playing a Dragon World deck with two copies of Fifth Omni Dragon Lord, Tenbu in my deck. If my flag is turned face down, do I automatically lose the fight because two of the same Omni Lord is in my deck?
 * A: No, you do not. Even if a flag is turned face down while fighting, the number of Omni Lord in the deck does not affect the fight.


 * Q2194: If my flag is turned face down, may I still cast Emblem of Omni Lords?
 * A: Yes, you can. Since Emblem of Omni Lords has the effect "You may use this card with all flags.", you can use it even if your flag is face down.