In PvP (Player vs Player) events, the player is matched against a deck built by another player. This game mode is not "true" PvP, since an AI (artificial intelligence) bot controls the enemy's play. The AI is inferior to a skilled player in both its gem matching and its card strategy.
PvP events are contrasted with PvE events, in which the player battles against pre-constructed enemy decks.
PvP events are often unpredictable due to the unknown nature of the opponent's deck.