PKQuests are reward systems for Player Killing. To begin a PKQuest simply type it (if its your first PKQuest, type PKQuest Complete). To complete a PKQuest you will need to kill four characters of variying classes. To see a cryptic message about each class you need to kill, type PKQuest. Once you have killed all the classes required, type PKQuest Complete and you will recieve your reward for your work. The kills should be status kills, so decapitating people who have just trained avatar will not help.