Cliff path
Everything from Under-Shrine Valley idol up to the Gun Fort approach.
Sculptor's Idol (Under-Shrine Valley)
Gravesite
From the sculptor's idol, make your way backwards to a platform with two Snake Eyes Spear-Bearers. From there, jump across the gap to a wall you can grab, and follow the path further on.
Pacifying Agent (ground)
Pacifying Agent (icicle)
Campsite
Follow the path until you reach a tree branch right in front of a Snake Eyes Spear-Bearer (second enemy since the Under-Shrine idol). Go up the climbable wall on the left and follow it until you reach a campsite.
Gun Fort approach
The ledge overlooking the a tall cliff with the Buddha's head statue on it, and the cliff face beyond the rope bridge.
Sculptor's Idol (Sunken Valley)
Buddha's Head
Cliff face
Gun Fort
Outside
Inside
Sculptor's Idol (Gun Fort)
Shrine
Caves
Reachable by continuing down from under the shrine floor.
Sunken Valley passage
The large lake with a rope bridge over it.
On a cliff ledge below the start of the bridge.
Riven Cave
Sculptor's Idol (Riven Cave)
Cliffs
Includes everything you can reach without dropping down to the poison-filled bottom of the valley.
Group of monkeys
Pacifying Agent (cliff edge)
Sculptor's Idol (Bodhisattva Valley)
Guardian Ape's Watering Hole
Travel
To acquire more lore/information about the Immortal Severance.
To Abandoned Dungeon and then Senpou Temple.
Completing Senpou Temple will grant you Puppeteer Ninjutsu, which is required to retrieve Dried Serpent Viscera further down the valley.
The ground level is accessible from the start, but you need Pupetteer Ninjutsu to complete the serpent shrine, and you don't receive instructions to go there until mid-game.
Cliffs
Give Rice to the Faithful One (Sunken Valley)
Next to the Bodhisattva Valley sculptor's idol.
Travel to Inner Sanctum to get more Rice
Ground level
Ledge on the way down from the idol.
Monkey island
Cave entrance
Cave
Small alcove
Serpent Shrine
Use Pupetteer Ninjutsu on the lone monkey cowering not far behind the serpent's head. It will distract the serpent, allowing you to grapple up and enter the shrine.