REDU format ruling
Curse of Fiend
Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)Change the battle positions of all Attack Position monsters on the field to Defense Position and vice-versa. These positions cannot be changed during the turn this card is activated except by the effect of a Spell, Trap or Effect Monster Card. You can only activate this card during your Standby Phase.
Rulings
Changes the battle positions of all Attack Position monsters on the field to Defense Position and vice-versa. These positions cannot be changed during the turn this card is activated except by the effect of a Spell, Trap or Effect Monster Card. You can activate this card only during your Standby Phase.
- This card must be Set in order to be activated during your Standby Phase. During your Standby Phase you flip up the face-down Curse of Fiend to activate its effect.
- Face-down monsters changed to Attack Position will have their Flip Effects (and when this card is flipped face-up Trigger Effects) activated [REF]. This is NOT a Flip Summon, and will not cause Swarm of Scarabs to activate its Trigger Effect.
- VS. Final Attack Order: While Final Attack Orders is active, you can change the Battle Positions of monsters with Curse of Fiend or Little-Winguard, but the Battle Positions are immediately changed back to Attack Position by Final Attack Orders.
- VS. Destiny Hero Diamond Dude: You cannot activate the effect of Curse of Fiend, because it can only be activated during the Standby Phase.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.