There are four designated piles for all players in a battle.
Library[]
The Library is a game zone only visible to you. In the game it's refered to by the notation "deck".
After a card has been successfully played, depleted or affected by certain effects, it is put into either the Depletion Pile, the Banish pile or the Ranged Graveyard.
If a player's library is reduced to 0, he loses the game.
Depletion Pile[]
The Depletion Pile is a game zone visible to all players and where successfully played non-ranged cards and depleted cards are put. Whenever you are dealt damage, cards equal to the amount of damage are put into your depletion pile. Every time you are healed, you put a random card from your depletion pile back into your deck and shuffle it afterwards.
Banish Pile[]
The Banish Pile is a game zone where cards can be put in. The effect "Banish" lets you or your opponent put a number of cards, determined by the triggering card, into yours or his Banish Pile. Potions that are depleted or played are put into the banish pile. Ranged attacks that are played are placed in the Ranged Graveyard which is in the Banish Pile.
The effect "Heal" only refers to your depletion pile, therefore banished cards cannot be returned to your deck with heal. Banished cards can be healed by various cards.
Ranged Depletion Pile[]
The Ranged Graveyard is a game zone where successfully played ranged attacks are put into.
Every player can look into the ranged graveyards of both players, since the effect heal only affects the depletion pile, cards in the ranged graveyard cannot be returned to the deck this way. Depleted ranged attacks still go to the depletion pile and therefore can be healed normally. Played ranged cards can be healed by various cards.