Quiet Death (Combat)Source Ultimate Intrigue pg. 89
You have learned to dispatch your enemies with the silence and grace of an accomplished assassin.
Prerequisites: Dex 19, Stealth 10 ranks, rogue level 10th.
Benefit: When you ambush an enemy or enemies that are unaware of your presence, you can roll a Stealth check with a –5 penalty. The result indicates the Perception DC to hear your attacks (rather than the normal DC of –10 to hear pitched combat) until an opponent’s first action, when the DC returns to –10. Other enemies present can still see the attack; Quiet Death only prevents the sounds of battle from alerting further enemies.