It was suggested that many different wishes of the secretive battle. What's in the game against real people is unacceptable. But he decided to offer his version of stealth combat.
1) Sneak. New skill that allows you to reduce the noise of steps in order to be able to sneak up behind another player and he would not have heard your steps from 20 meters now. Sneak in armor Skill is not active.
2) The ability to instantly kill. By fatal blows, such as the cutting of the throat, or Spike. All strikes have blocked various armor. For example Mail Helm Spalleti by throat-slitting, and armor save from spiking.
No fading out of sight should not give skill. But the opportunity to behave discreetly and quietly kill needed.