Stalker (perk)

Stalker: Gain one/one/one/two Token/s for Surprise Attacks. Every Token decreases the sound volume of your movement actions by -1/5/7/10%. Tokens capped at 10. Gain 50% more points for Stealth actions.

Find more perk info out here: Perks

Quotes:

 "You must know, how to sneak up to them"