"Kill me and you lose your karma"
Karma is a measure of how much damage a player can deal in a round. Karma is lost when an Innocent kills another innocent, a Traitor kills another Traitor, a Detective kills an innocent, a Detective kills another Detective, or an Innocent kills a Detective. The highest karma can go to is 1000, possibly higher on some servers. If a player's karma is low, they will not do as much damage as a player who has high or full karma. Karma can be increased through killing Traitors if you're an Innocent/Detective and vice versa. An Innocent player with high karma will not lose as much karma for killing another Innocent with low karma as would be lost for killing another Innocent with high(er) karma. Certain servers also have a "Karma ban," used when someone's karma gets too low.
Most servers have a karma ban if your karma goes below 500