At the start of the Trial, 4 random Hooks, as well as the Basement Hooks, are changed into Scourge Hooks:

The Auras of Scourge Hooks are revealed to you in white.
Each time a Survivor is hooked on a Scourge Hook, the following effect applies whenever you are farther than 24 metres from the hooked Survivor:
Accelerates the Sacrifice Process by 10/15/20 percent.

Performing the Damage Generator Action on a Generator triggers Nowhere to Hide:

The Auras of all Survivors within 24 meters of your position are revealed to you for 3/4/5 seconds.

Whenever a Generator is repaired to 90 percent, Survivors repairing it are faced with continuous Skill Checks.
If they miss one or stop repairing, the Generator becomes blocked for 16/18/20 seconds.
Merciless Storm can only trigger once per Generator per Trial.

You become obsesses with one Survivor.  When your obsession is hooked, Furtive Chase receives a token, up to a maximum of 4 tokens.

Each token decreases your Terror Radius by 4 meters while in a chase.

When a Survivor rescues the Obsession from a hook, the rescuer becomes the Obsession.