At the start of the game, the Deck is shuffled, and then placed face-down in the Deck area of the field. All cards in the Deck remain face-down throughout the game, and no player may view the contents of any player's Deck unless a card Ability allows them to.
Deck construction restrictions
The Deck must contain at least 60 cards. There is no limit to the number of cards inside the deck as long as there are at least 60 cards.
A player's Deck can contain a maximum of four copies of any single card with the exact same Card Name. For Character cards, the Card Name includes the Character Name and Version. For example, Stitch - New Dog is a treated as a different card from Stitch - Rock Star, so a player may play four copies of each card in their Deck. Because this is based on card names, it means that enchanted cards count as being the same card as their non-enchanted counterparts. A player may not have four of each, only up to four in total.