PvP, short for Player vs. Player, is when two or more players fight.
The mechanics follow a flagging system, as well as static PvP zones at certain points of interest; fight for control over cities, castles, caravans, or hunting grounds.
All players start off flagged as innocent. Players who attack innocent players become flagged as combatants. An innocent player who fights back is turned into a combatant as well, while an innocent player who fights back remains innocent. If a player dies innocent, combatants responsible for the death gain corruption and become flagged as corrupt.
Corruption is used to scale penalties made against players who kill innocent players. Corrupt players can be attacked by innocent players without flagging the innocent players as combatants.
Player killing, also known as PKing or ganking, is when players can attack each other in the open world outside of PvP related events. Combatants who take part can be made corrupt, as players that are attacked may be innocent.
Caravans are used to escort the shipment of goods along a road. Players may attack caravans, although NPC guards and other players can be hired to defend them. Successfully escorting or sacking a caravan will provide a reward to the victors. Signing up to protect or attack a caravan flags players as combatants, so taking part in a raid against a caravan may yield no corruption.
Nodes may be besieged by players. When this happens, players can either choose to attack or defend the node. A successful siege can either degrade or destroy a node. Signing up to protect or attack a city flags players as combatants, so taking part in a siege against a city may yield no corruption.