Tengu format ruling
Future Fusion
Card effect (current official text)During your 1st Standby Phase after this card's activation: Show 1 Fusion Monster in your Extra Deck and send the Fusion Materials listed on it from your Main Deck to the GY. During your 2nd Standby Phase after this card's activation: Fusion Summon 1 Fusion Monster from your Extra Deck with the same name as the monster you showed, and target it with this card. When this card leaves the field, destroy that target. When that target is destroyed, destroy this card.
Rulings
- If you cannot Special Summon, you cannot activate this card.
- This card’s Special Summon cannot be negated by "Thunder King Rai-Oh" or "Horn of Heaven".
- You can chain "Royal Oppression" to this card’s activation. (but not when the Monster is Fusion Summoned).
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.