Outward takes some of the key principles behind such modern classics as is Breath of the Wild and applies them to a PC RPG title - various secret loot included. Outward Ghost Pass, for example, has a secret Legendary Chest!
Outward Ghost Pass Legendary Chest can be found to the East, starting from the central mountain of the game map, and here, you're going to find out what sort of stuff you can expect as you make your way through the Ghost Pass.
Outward Ghost Pass Secret Legendary Chest Location
In Outward, Ghost Pass is an abandoned dungeon-like construct that's perpetually dark. Not that various signs of a struggle and ample amounts of spilt blood aren't helping set the mood, either. Expect numerous ethereal skeletons and other assorted enemies, so it would be smart to come well-equipped.
The easiest way to go about looting the Legendary Chest of Ghost Pass is to allow one of the ethereal enemies to take you down, which will result in you subsequently waking up in their dungeon. You'll have no choice but to fight your way out, and when you finally reach the exit from this dungeon (you'll recognise it by a prominent door with a blue light shining above it), go in the opposite direction until you reach another large room, the centerpiece of which will be the Legendary Chest.
This will contain some substantially powerful loot, including weapons and armour, and at least a few of these pieces will come in handy in your future travels.
For a concrete (if lengthy) playthrough of Ghost Pass, check out the video featured below.