In PvP (Player vs Player) Events, the player is matched against decks built by other players for the same event. 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.