You become obsessed with one Survivor.
Each time you hit a Survivor other than your Obsession with a Basic Attack, Save the Best for Last gains 1 Token, up to a maximum of 8 Tokens:

Gain a stack-able 5 percent Cool-down reduction on successful attacks per Token, up to a maximum of 40 percent.
Each time you hit your Obsession with a Basic Attack, Save the Best for Last loses 4/3/2 Tokens.

When the Obsession is sacrificed or killed, you can neither gain nor lose any more Tokens.
You can only be obsessed with one Survivor at a time.

Whenever a Generator is repaired to 70 percent, you benefit from the following effects:
Triggers a Loud Noise Notification for that Generator, revealing its location.
Grants the Undetectable Status Effect for the next 12/14/16 seconds.
Tinkerer can only trigger once per Generator per Trial.

Wounds inflicted by Basic Attacks cause Survivors to suffer from the Hemorrhage and Mangled Status Effects:

Increases the Bleeding frequency by 50/75/100 percent.
Increases the Regression rate at which partial Healing Progression is lost through Haemorrhage by 15/20/25 percent.
Both Status Effects are removed once the Survivor is fully healed.

The Auras of Survivors within 2/3/4 meters of any Dull Totem are revealed to you.

When another Perks Hex Totem is cleansed or blessed, its Hex is transferred to the Hex: Undying Totem, including any accumulated Tokens, disabling Hex: Undying instead.
The Hex effects persist until its Hex Totem is cleansed.

Each time a generator is repaired, all windows and vault locations within 32 meters of it are blocked for all Survivors for the next 30 seconds.

Survivors within your Terror Radius suffer from inefficiency:

When using an Item, its Depletion rate is increased by 80/90/100 percent.