Book of Moon [OP13-EN001] Ultimate Rare SV057 You can only activate 1

You can only activate 1 "Cynet Backdoor" per turn

or you're just starting to build your Extra Deck with cards from Duel Devastator

Set: League & Championship Cards Type: Supporter Rarity: Holo Rare

Set: Premium Pack 2 Card type: Effect Monster Rarity: Secret Rare Attack: 1500 Defense: 1100 You can discard this card to the Graveyard to add 1 "Valhalla

You can only use each of the following effects of "Super Quantum Red Layer" once per turn

Book of Moon [OP13-EN001] Ultimate Rare SV057 You can only activate 1Set: OTS Tournament Pack 13 Card type: Quick Play Spell Rarity: Ultimate Rare Target 1 face up monster on the field; change that target to face down Defense Position.