"Kill Steal", or killing a monster which doesn't belong to the player, (Someone else/some other party is attempting to kill it or the monster is attacking them) is a bannable offense, and very poor manners. Don't do it!
Gravity Interactive officially categorizes Kill Stealing under Harassment. It is not uncommon for mistakes to happen, and there is a threshold for determining if a behavior was harassment/KSing. A single incident where someone comes up and takes a whack or two at your monster is NOT KSing. A person who makes a habit of attacking your monsters IS KSing. To successfully report an incident of KSing you need to include screenshots of the offender attacking your monsters on a few different occasions. You should also try and have before and during screenshots so that the GMs can clearly see that the offender was attacking YOUR monster.
|Monsters in Ragnarok Online|
|Race||Angel · Demon · Formless · Insect · Fish · Demi Human · Undead · Dragon · Plant · Brute|
|Element||Holy · Shadow · Neutral · Water · Fire · Wind · Earth · Ghost · Poison · Undead|
|Boss Protocol · MVP (Free for All) · Size · Kill Stealing · Monster Skills|