1:when あなた reach the 2nd section of the cave head right pick up the shotgun turn left & fight him
use the shotgun または a grenade when he is covered in bees.

2:when fighting the fear of course あなた can't see him
when あなた are in the factory where あなた get too sokolov(not during vartouis mission)in the room where sokolov was held there is a locker open it & there あなた will find the terminal goggles use it to see the fear even when he is in camo.

3:after あなた defeat the pain あなた walk a river when あなた are in the end of the river turn left.there will be two soldiers take them out get on the platform...