World of Warcraft contains a variety of mechanisms for player versus player (PvP) play. Players on player versus environment (PvE) servers can opt to "flag"
themselves, making themselves attackable to players of the opposite faction. Depending on the mode of the realm,
PvP combat between members of opposing factions is possible at almost any time or location in the game world—the only exception being the starting zones,
where the PvP "flag" must be enabled by the player wishing to fight against players of the opposite faction.