Crit from Concealment

You may call Crit ("Critical") damage whenever you inflict damage with a melee attack, packet, or thrown weapon to a target from Concealment. Critical damage cannot be Absorbed, Resisted, or Withstood and bypasses most defenses. If you are subdued by Critical damage, you are immediately slain. If you gain this effect through a weapon property, it only applies to attacks with that weapon.