Unlike the instanced PvP in battlegrounds or arenas, open PvP is not restricted to a specific zone and can be practiced anywhere – or at least in designated free areas, that is, areas without access restrictions regarding level or number of players. This creates an imbalance. Feared players in open PvP, who specifically hunt weaker players, are also called player killers (PKs). Open PvP encompasses a wide range from tactical play around fortifications, castles, and key points, to hunting and killing significantly weaker opponents who wish to engage in PvE.