Each time a Survivor other than yourself is killed or sacrificed, Sole Survivor gains 1 Token, up to a maximum of 3 Tokens:

Each Token grants a stack-able radius of 20/22/24 metres within which the Killer is unable to read your Aura, up to a maximum of 60/66/72 metres.
Once you are the last Survivor standing, you benefit from the following effects:

Increases your Repair speed of Generators by +75 percent.
Increases your Opening speed of the Exit Gates and the Hatch by +50 percent.
Increases the odds of becoming the Killers initial Obsession by +100 percent.

The Killer can only be obsessed with Survivor at a time.

Unlocks potential in your Aura-reading ability:
Each time a Generatoris completed, Dark Sense activates:

The Aura of the Killer is revealed to you for 5/7/10 seconds, as soon as they come within 24 metres of you, after which Dark Sense deactivates.

While being carried by the Killer, the following effects apply:

Increases the intensity of the Struggle Effects on the Killer from your Wiggling by 60/70/80 percent.
Obscures the Auras of all Hooks from the Killer's Aura-reading abilities within 16 meters.
Fills your Wiggle Meter by 33 percent of your current Wiggle progression upon landing, when the Killer drops from great heights.

Increases your Action speeds in Repairing, Healing, Sabotaging, Unhooking, Vaulting, Cleansing, Blessing, Opening, and Unlocking by 3/6/9 percent when in the Injured State.

When another Survivor loses a Health State within 32 metres of your location while you are in the Injured State, you benefit from the following effect:

Grants 40/45/50 percent of your missing Healing Progression to your Health Bar.

When starting to run, break into a sprint at 150 percent of your normal Running Movement speed for 3 seconds.
Sprint Burst causes the Exhausted Status Effect for 60/50/40 seconds.
Sprint Burst cannot be used when Exhausted.