Quick Answer
High-value detours include Earth-Shakers on Underground Level 4, Flashing Void in a slide-through cave at Mount Oe’s Castle Courtyard, and Still Water in the northeast of the Swamp of Arashiyama. Explore these areas as their story routes open. Use Oni Vision for hidden interactions and keep a manual save before The Clash at Rendaino for cleanup.
- Laboratory pickup
- Earth-Shakers
- Mount Oe pickup
- Flashing Void
- Arashiyama pickup
- Still Water
- Cleanup save
- Before the final mission
Three useful Armament detours
| Area | What to find | Landmark |
|---|---|---|
| Underground Laboratory | Earth-Shakers | Level 4, room after the fan puzzle |
| Mount Oe | Flashing Void | Castle Courtyard; slide into the cave |
| Swamp of Arashiyama | Still Water | Chest in the northeast corner |
Use Oni Vision before abandoning a dead end
Pulse Oni Vision when the route or an interaction is unclear. At thread barriers, follow the revealed connection to its Thread Genma. Destroying that creature clears the path; repeatedly striking the barrier does not.
Treasure-related Oni Vision skills help with cleanup. Learn the available treasure and search-range improvements, then check side passages while moving between objectives. If the required interaction is still locked, return after advancing the story rather than assuming a permanent miss.
Separate story destinations from optional pickups
The Underground Laboratory and Mount Oe are part of the campaign. Their extra chests are detours within those locations, not entire optional zones that require an ending checklist.
Use Mysteries of Kyoto and Chance Encounters for side-quest rewards. If you want charms in particular, their mission rewards are listed in Charm Locations; searching a random cave chest is a poor substitute for checking the relevant quest.
A practical cleanup order
- Finish the current story objective and activate its Spirit Mirrors.
- Check the nearby Armament chest before leaving that region.
- Return to earlier blocks when a new Oni ability makes them usable.
- Complete the side quests that award your preferred charms.
- Save separately before The Clash at Rendaino, then finish outstanding exploration.
Direct answers
Frequently asked questions
Is Mount Oe a secret optional area?
Mount Oe is a story location. The Flashing Void chest is an extra pickup to check there.
Where is Flashing Void?
In a cave reached by sliding through its entrance in Mount Oe’s Castle Courtyard.
Where should I save for collectible cleanup?
Keep a manual save before starting The Clash at Rendaino.