All 8 End of Abyss Vault locations and how to get every Vault Key: 5 drop from story bosses, 3 from optional bosses, plus the Suit Mod each Vault holds.
End of Abyss Vault Locations: All 8 Vaults and Vault Keys
End of Abyss has exactly 8 Vaults, 8 Vault Keys, and 8 Suit Mods inside those Vaults — plus 2 Suit Mods found outside any Vault. Five keys drop from story bosses you have to kill anyway; the other three come from optional fights, which is why a clean story-only run leaves you three Vaults unopened.
What a Vault is: a small hidden room holding one passive Suit Mod, sealed until you spend a Vault Key. Opening all eight unlocks Dungeon Crawler; opening the first unlocks Vault Entry. None of it is missable.
Walkthroughs use vault as a movement verb. GameRant's Habitation Sector route says to "vault through the window on the east side of that hallway" — a traversal move, and the room it drops you into holds the Riot Breaker shotgun, not a Suit Mod. If a step list says "the Vault," check whether the sentence has a window in it. Real Vaults are key-locked rooms.
All 8 Vaults: sector, floor, key, and Suit Mod
Rows are ordered by when you can realistically open each one, not by an in-game index — the game does not number its Vaults on screen, and no published guide pairs a key to a specific door. Every source describes the requirement as plain "a Vault Key," so read the eight as a pool. Floor codes follow the sector and floor reference.
| # | Vault location | Suit Mod inside | What you need beyond a key |
|---|---|---|---|
| 1 | Habitation Sector, F1, end of the hall | Equipment Belt | Nothing — the earliest one you can reach |
| 2 | Factory West, F2, left side | Blast Resistance | An Explosive Charge to blow the wall |
| 3 | Communication Center, F2, below the trapdoor | Vitality Enhancer Mk. II | Finish the 3-SCU objective first |
| 4 | Waterworks, B3, the drained pit | Acid Neutralizer | The Grappling Hook, then the pump and an Energy Node door |
| 5 | Reactor, B4, top left corner | Heal Amplifier | Deep story progress in the Reactor's lower floors |
| 6 | Containment Sector, F1, bottom right | Proximity Sensor | The Incinerator, to burn the Parasitic Growth hiding the ladder |
| 7 | Infirmary, B1, left side | Auto-Defibrillator | Infirmary Key plus Restricted Access Keycard |
| 8 | Lower Levels, F1, door on the right | Experimental Core | Level 3 Access card, which needs the Level 2 card first |
Two rows catch people out. Row 6 needs the Incinerator, handed to you only in the last area of the story — so the Containment Sector Vault is really a late-game pickup even though the sector itself is mid-game. Row 8's Level 3 Access card is a two-step chain: the Level 2 card sits in the Lower Levels behind a wall you burn with the Incinerator.
Where all 8 Vault Keys come from
| Key # | Boss | Story or optional | Where the fight happens |
|---|---|---|---|
| 1 | Husk Cluster | Story — first boss | Habitation Sector, guarding the shuttle station route |
| 2 | Husk Centipede | Story — second boss | Reactor, B2, after the final Power Cell |
| 3 | Security Sentinel | Story — an SCU boss | Factory West, behind a charged weak floor |
| 4 | Drowned Husk | Story — an SCU boss | Waterworks |
| 5 | Radiation Host | Story — an SCU boss | Containment Sector, Isolation Cistern |
| 6 | Husk Centipede, fought again | Optional | Reactor Pool, after the Waterworks drain chain |
| 7 | Brood Keeper | Optional | Ventilation Tunnels |
| 8 | Morgue Dweller | Optional | Infirmary, B1 |
The Husk Centipede is the only boss that pays out twice — a story fight for Key #2, an optional rematch for Key #6. Details on each fight, its preconditions and its drops are in the named boss reference.
The achievement and the full-game walkthrough both call this boss Radiation Host. The mod-location guide that maps it to Vault Key #5 calls it Radiant Host. Same fight, same key — search both.
Why only 5 of the 8 keys come from the main story
Vault Keys drop as boss rewards, and the five story bosses are the five the game has to put in front of you: the Husk Cluster and Husk Centipede gate the opening reactor push, while the Security Sentinel, Drowned Husk and Radiation Host are the three SCU-override bosses you cannot skip. Kill those five and you hold keys for five Vaults without leaving the main route.
The other three sit behind fights the story never asks for. The Brood Keeper hides in the Ventilation Tunnels, reachable only by blowing open a weak wall off the easternmost Factory East entrance, dropping to F3, and using a Ventilation Maintenance Key plus the Grappling Hook. The Morgue Dweller waits at the end of the Infirmary, an optional late-game area entered only after burning a Parasitic Spire in the Lower Levels to earn the Infirmary Key. The third optional key is not even a new enemy — it is the Husk Centipede at the bottom of the drained Reactor Pool.
So the split is not arbitrary gating: one key per mandatory gate, plus one key per optional boss.
The 2 Suit Mods that are not in Vaults
The game has 10 Suit Mods total, and only 8 live in Vaults. The other two are the trap for anyone who assumes "Suit Mod equals Vault":
- Vitality Enhancer Mk. I — you start the game already wearing it.
- Radiation Protection — not in a Vault at all. It sits in a small room off a lockdown encounter in Factory East B2, opened with the Basement Keycard from the Containment Sector.
Radiation Protection is effectively story-gated because the Containment Sector drains your health until you wear it; IGN's reviewer called the mod pure relief, since the game never warns you radiation is the thing hurting you. Slot count and Energy Cells are covered in the Suit Power and Suit Mod breakdown.
Shortest route to open all 8 Vaults
- Story up to the 3-SCU objective. Keys #1 through #4 arrive automatically across the Habitation Sector, Reactor, Factory West and Waterworks. Open the Habitation Sector F1, Factory West F2 and Communication Center F2 Vaults as you pass — three Vaults before the SCU hunt even ends.
- Containment Sector. Take the Radiation Protection mod on the way in, then the Radiation Host gives you Key #5. The Grappling Hook is picked up inside this sector, and it unlocks two later steps.
- Waterworks B3. With the hook, run the pump and drain the pit for the Acid Neutralizer Vault.
- Optional fights. Brood Keeper in the Ventilation Tunnels for Key #7, the drained Reactor Pool for Key #6, then the Infirmary for Key #8.
- Lower Levels, last. Burn the walls with the Incinerator, chain the Level 2 then Level 3 Access cards, and open the Experimental Core Vault. The Incinerator is also what unlocks the Containment Sector Proximity Sensor Vault.
Because the shuttle network does not reach every sector, several legs are long walks — check the shuttle station list before planning, and the SCU and Central Elevator progression order for where the story hands you the hook.
Every Vault and key can be collected after the main story, so there is no need to burn a boss you have not beaten yet just to chase a mod.
Vault Entry and Dungeon Crawler
Two achievements track this system. Vault Entry unlocks when you open your first Vault — almost everyone gets it. Dungeon Crawler unlocks when all 8 are open, and it is what separates a story-clear save from a 100% save, because it needs the three optional bosses too.
The official Epic Games Store achievement list carries live per-achievement unlock rates, still climbing as more players finish. For the broader rarity picture, see the trophies and achievements ranking.
Official source: End of Abyss achievements on the Epic Games Store
FAQ
Are there 8 or 10 Suit Mods in End of Abyss? 10 total, but only 8 are in Vaults. Vitality Enhancer Mk. I is equipped from the start; Radiation Protection is a story pickup in Factory East B2.
Which boss gives the most Vault Keys? The Husk Centipede, which drops two — Key #2 in Reactor B2, and Key #6 on the rematch at the bottom of the drained Reactor Pool.
Can I open a Vault without a Vault Key? No. All eight keys come from bosses; there is no crafting, chest or keycard alternative.
Is the Radiation Protection mod inside a Vault? No. It is west of a lockdown encounter in Factory East B2, opened with the Basement Keycard.
Are the Vaults missable? No. All eight can be opened after the main story. The only way to lose trophy eligibility is activating cheat codes from the Logbook.
Sources
Vault, key and Suit Mod data comes from 100% Guides' Vault and Mod guide, unlock conditions from their Trophy Guide, sector/floor details cross-checked against the GameRant full-game walkthrough. Reflects the launch build as of 2026-10-03.
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