Lost Deck

The "Lost Deck" (ロストワールド Rosuto Wārudo) is a deck that contain cards from Lost World. The Lost Deck is separate from the main deck and you must have 30 cards in the Lost Deck. Card sleeves for the Lost Deck must be different to your main deck.

You can only use the Lost Deck when your flag is "Lost World". By activate the Lost World's "Lostnify", remove the main deck from the fight, shuffle the Lost Deck, and replace with it.

You cannot shuffle any cards from the main deck into the Lost Deck. If there was an effect like "Overturn Ice Emperor, Miserea" that you need to return cards to the deck, cards from main deck will remain there since it cannot shuffle into the Lost Deck.

The Lost Deck may only contain a maximum of 4 cards with the same card name (excluding the buddy monster). Even if a card has a different ability or illustration, the maximum of 4 copies is kept. The card name is written in the Name section.

If a card effect states that "This card is also regarded as X", only the name printed in the name box will count towards the "Max 4 copy" rule. (See: Super Lethal Formation/Rulings). Both cards will have the same name, and are viable targets for any card that may support them.