Similar to .hack sign the series, anyone can attack anybody whenever. However, this action i frowned upon and you characters status is changed from roleplayer to pker. This will be indicated by some mark like a change in color or symbol. While a pker monsters become much more aggresive towards you and you recover by half each match(maybe double). Also, a bounty is placed on you based on the difference of you and who you kiilled along with the number you killed. Players can seek a bountyhood as you will to kill the pker and get the reward(3/4 money and inventory). If someone gets high enough as a pker they may potential create their own hide outs or mafias.