Tengu format ruling
Falling Down

Card effect (current official text)Activate this card by targeting an opponent's monster; equip this card to it. Take control of it. Destroy this card unless you control an "Archfiend" card. During each of your opponent's Standby Phases: You take 800 damage.
Rulings
- If there are no Archfiends on your side of the field, Falling Down is destroyed immediately, even in the middle of a chain.
- The Archfiend you need for Falling Down doesn't have to be a monster. Cards like Axe of Despair, or an Archfiend monster equipped to your Relinquished, will prevent Falling Down from being destroyed.
- You can activate Falling Down when there are no Archfiends on your side of the field, but it is destroyed immediately before it is equipped to a monster.
- You cannot use Barrel Behind the Door against the damage from Falling Down because you cannot use Barrel Behind the Door against a Continuous or Equip Spell Card.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.