Hell is Us Vault of Forbidden Knowledge Codes

Vaults of Forbidden Knowledge are Hell is Us at its most distinctive. Instead of typing digits into a keypad, you rotate a dial through emotional keystones — Rage, Ecstasy, Terror, Grief, Vigilance, Loathing, and related states tied to the Lymbic system. Six Vaults of Forbidden Knowledge are scattered across Hadea. Each guards Relics, weapon glyphs, and lore that explain how the country unraveled. Missing a vault does not always hard-block the campaign, but it frequently delays power spikes before Hollow elites and late Timeloops — and blocks several platinum trophies until every vault is unsealed.

Research Items and Tania

After Tania joins you on the APC in Act 1, open the Research option and submit Research Items you pick up during exploration. There are 45 Research Items split across six categories (Ancient Hadea, Order of the Eye, Lymbic Invasions, The Vigil, The Conspiracy, and The Civil War). Each hand-in fills Tania’s research gauge; when a category completes, she reveals a vault location, clue text, and the matching emotion dial code on your Datapad Research tab under Vaults of Forbidden Knowledge.

You can enter vault codes early if you already know the emotion sequence from a guide — the dial accepts correct input before every in-game clue is discovered. Research trophies and Tania’s full articles still require turning in every Research Item, so completionists should submit items as they find them rather than only chasing dial shortcuts.

Two vault emotion sequences are widely documented as fixed orders from launch: Acasa Marshes and Lake Cynon. The remaining four vault codes unlock through Tania’s gauge — cross-check your Datapad after each research milestone. Numeric locks nearby — such as Outpost 08’s gate — are listed under door and gate codes. Optional Mysteries in the same regions often hide Research Items; see Mysteries guide for routing without spoiling every solution.

Post-launch patches through 1.7 have not changed vault sequences or Research Item counts per community verification — see patch news if a future hotfix mentions Investigation retroactive fixes.

How vault dials work

Approach the vault interface and cycle the dial through named emotions. The correct order must be entered sequentially; partial matches do not carry over between attempts. Clues arrive through Datapad Investigations, Tania research writeups, environmental murals, NPC testimony, and occasionally audio logs near the vault entrance. Because the game lacks a map, players often discover the vault before they discover every keystone name — keep exploring the surrounding district until your Datapad registers all required emotions.

Vault rewards typically include Relic pieces, Lymbic upgrades, or glyph slots that complement melee combos and Healing Pulse sustain. If you are optimizing a first playthrough, plan vault attempts after clearing local Timeloops; open loops can respawn enemies across the approach path.

Acasa Marshes vault sequence

Order: Rage → Ecstasy → Terror → Grief

The Acasa Marshes vault sits near optional military ruins and the Observation Outpost 08 chain. Expect to tie clues to Outpost paperwork, Watcher’s Nest Investigations, and marsh-side shrines. Community routing usually looks like this:

1. Secure Outpost 08 access with gate code 151991 from the door codes page.
2. Finish Watcher’s Nest surveillance puzzles so Datapads reference emotional keystones.
3. Sweep marsh Timeloops for murals that name Rage and Terror explicitly.
4. Return to the vault dial and enter the four-emotion chain without pausing.

Ecstasy and Grief clues sometimes hide in easily skipped side rooms. Use your KAPI drone to scan upper ledges — several marsh collectibles sit above the waterline. If an emotion name never appears in your Investigations, you are likely missing an optional Good Deed or a destructible wall along the marsh trail.

Lake Cynon vault sequence

Order: Vigilance → Grief → Loathing → Terror

Lake Cynon combines forge pillars, underwater routes, and a vault that expects four different emotions than Acasa. Grief appears in both vaults, but the surrounding order changes completely — do not reuse the marsh sequence here.

1. Complete Lake Cynon pillar and forge puzzles documented in the puzzle solutions guide.
2. Read forge technician Datapads that mention Vigilance and Loathing.
3. Close nearby Timeloops so elite patrols do not interrupt dial input.
4. Enter Vigilance → Grief → Loathing → Terror at the vault interface.

Lake Cynon rewards often synergize with mid-game Lymbic weapons. If damage feels flat against Auriga Hollows, backtracking here is usually faster than grinding random mob camps.

Remaining four vaults

Tania’s research gauge unlocks the other four Vaults of Forbidden Knowledge as you complete each Research Item category. The Datapad stores location hints and emotion orders once Tania deciphers them — you do not need to memorize every chain if you submit items regularly at the APC. Platinum hunters should plan vault sweeps alongside Good Deeds and Timeloops so Amine Prisms and guardian fights do not interrupt dial input.

Track progress on the platinum checklist and exploration checklist when you prefer tick boxes beside the game.

Keystone Investigations worth completing first

Three Investigation threads repeatedly feed vault knowledge across Hadea:

• Keystone of Terror — links marsh anomalies to late-game Lymbic lore.
• Keystone of Rage — required context for Acasa ordering.
• Keystone of Ecstasy — easily missed if you skip optional NPC rescues tied to Good Deeds.

Track these alongside vault entries so you do not duplicate backtracking. Good Deeds that keep NPCs alive sometimes unlock extra keystone dialogue; killing optional hosts early can silently remove clues.

Vaults versus safes and computers

Vaults reward build-defining items but demand exploration breadth. Safes and computers — covered on the safe and computer codes page — reward quick numeric entry once you know the digits. Door keypads sit between the two: usually clue-light but mandatory for routing. Use the Code Finder when you forget which lock type you are facing; filter vault to hide numeric noise.

Speedrun and cleanup notes

Speedrunners typically delay vaults until fast travel routes exist through Timeloop closures. Completionists should hit both early vaults before entering Auriga Museum’s B4 Timeloop wing — the power spike makes museum combat noticeably smoother. New Game Plus rules have not changed vault sequences in post-launch patches as of community verification.

Vault sequence summary

Vault	Sequence	Region
Acasa Marshes	Rage → Ecstasy → Terror → Grief	Acasa Marshes
Lake Cynon	Vigilance → Grief → Loathing → Terror	Lake Cynon
Vaults 3–6	Unlocked via Tania research gauge	See Datapad after each category

If the dial rejects a correct sequence, reload the area to clear a rare interaction bug, then confirm every keystone Investigation is marked complete on the Datapad.