Karma refers to the alignment system which affects your relationship to players and NPC’s, in regards to PvP. You gain karma by killing monsters.
When you initiate open world PvP, or flag on another player, you lose karma for assaulting that player. If you strike a death blow, you lose more karma for murder.
If you go below 0 karma, you are permanently flagged until you raise your karma, and NPC guards will kill you on sight.
Customer Support will not restore karma loss on your character.