When u pk a player, u are given a Eval Score ie 300. By killing mobs it will drop for example 10 per mob, lower u get it the lighter the red ull become til eventually u are white :)
karma decreses either when you gain xp or lose xp
the karma lost is directly related to the amount of xp you gain/lose
at 78 you might gain 15k xp per mob which is about 50 karma lost
if you were to take a 1% xp loss you could work off like 4 pks
just be careful not to become chaotic player. after 5th pk u ll start dropping things on death. and in higher lvls, it would be really bad to drop your weapon or your helmet.
in case u got more than 5 pks already, there s a quest in hunter's village that erases some of them, or maybe all, not sure. never done it
why? with each bot you kill, you're one step closer to droping your Armor, Weapon, and anything else you have on you.
now, killing real players is fun, cause at the very least, you hear them whyne, cry and complain, where as bots just die. which by the way by killing bots, you're actually doing them a favor cause they'll now spend less time killing themselves on towns guards :p