Ghost of Yotei contains 11 Fox Den locations (Inari Shrines). Finding all Fox Dens and then collecting the golden fox mask at the Hunting Camp Hideout unlocks the Guardian of Inari trophy.
At Fox Dens you will find a little fox, go near him and he will lead you to a nearby fox shrine (Inari Shrine). Run after the fox until you reach the shrine and pray at it by swiping down on the Touchpad, this completes the Fox Den. The Fox Dens get marked on the map when you go near them.
Nothing is missable, everything can still be done after the story in free-roam.
Collectibles Overview:
Video Guide
Yotei Grasslands
1 – Lake View Fox Den (Charm of Uncanny Aim)
2 – Flowing Water Fox Den (Charm of Assassin’s Resolve)
3 – Grassy Hill Fox Den (Charm of Brutal Volley)
Ishikari Plain
4 – Fire Fox Den (Charm of Resolute Victory)
5 – Twin Path Fox Den (Charm of Enduring Resolve)
Tokachi Range
6 – Warm Plains Fox Den (Charm of Archer’s Fortune)
7 – Whispering Fox Den (Charm of Swift Reward)
Nayoro Wilds
8 – Clear Water Fox Den (Charm of Generous Opponents)
Teshio Ridge
9 – Winding River Fox Den (Charm of Opportunity)
10 – High Wall Fox Den (Charm of Lingering Shadows)
Oshima Coast
11 – Blushing Forest Fox Den (Charm of the Prepared)
Guardian of Inari Trophy & How to Get Fox Mask
After completing all 11 Fox Dens, you must go to the Hunting Camp Hideout (Sanctuary Grove) in the north-east of Teshio Ridge. You access this location by going through the Sarufutsu Lighthouse.
There will be a locked door and 4 fox statues there. You must spin the foxes on the left to face each other, and also have the foxes on the right face each either. Then you can pick up the small fox statues and place them on the pedestal at the door. Go through the door and follow the path behind until you reach the end of the area. There you must follow a little bear, then a woman opens the door and talks to you. She will reward you with the Fox Mask and the 
Guardian of the Inari trophy unlocks right when you get the mask.
If you’ve been to this area before you can simply fast travel there and talk to the woman in the house.
For all other collectibles refer to Ghost of Yotei Collectible Guide.
Marlon says
Got all 11 of them didn’t pop for me…???
Staurt says
I had to travel to the Sanctuary Grove to meet a woman. You may or may not have discovered that area yet. Its near the Sarufutsu lighthouse – which also to be honest you may also not have found. But that all might give you a clue to search online for :-)
ABHI says
SAME HERE , DID NOT POP UP
sleepneeded127 says
Go to Sanctuary Grove after getting the last den. A merchant bubble will pop up if you have already visited. If not it is located in Teshio Ridge on the North East.