All 7 named End of Abyss bosses with their sector, floor, what they drop, and the trophy that tracks them. Includes the second Husk Centipede fight.
End of Abyss Bosses: All 7 Named Bosses, Where to Find Them
Seven named bosses gate the story in End of Abyss, in a fixed order: Husk Cluster, Husk Centipede, Security Sentinel, Drowned Husk, Radiation Host, Failed Experiment and Fractured Being. Five hand you a Vault Key, one hands you the card that opens the final door, and two more fights sit off the critical path. Each is below with its sector, the gate in front of it, and the trophy that tracks it.
Official source: Section 9 Interactive — End of Abyss confirms PS5, Xbox Series X|S and PC (Epic Games Store) as the platforms. There is no Steam build, so achievement names quoted here are PlayStation or Epic wording.
All 7 named bosses at a glance
| # | Boss | Where | What gates it | Trophy | Drops |
|---|---|---|---|---|---|
| 1 | Husk Cluster | Habitation Sector, past the shuttle entrance room | Nothing — it sits on the only route to the Shuttle Control | Shuttle Station Cleared | Vault Key #1 |
| 2 | Husk Centipede | Reactor B2, middle room, after the final Power Cell | The B3 lockdown encounter plus the Security System Terminal | Now There Are Two of Them | Vault Key #2 |
| 3 | Security Sentinel | Factory West, below a blown-up weak floor | Mechanical Crank, three-node Energy Node Door, Explosive Charge | Sentinel Shutdown | Vault Key #3 |
| 4 | Drowned Husk | Waterworks, second ladder down | Operations Key from a workbench in the flooded room | Giantslayer | Vault Key #4 |
| 5 | Radiation Host | Containment Sector, inside the Isolation Cistern | Radiation Protection Suit Mod fitted at a Restoration Pod | Radiation Contained | Vault Key #5 |
| 6 | Failed Experiment | Lower Levels, Neural Chamber | Level I Access keycard, then the Incinerator | Specimen Terminated | Neural Chamber Access card |
| 7 | Fractured Being | Lower Levels, north of the Neural Chamber | The Neural Chamber Access card from boss 6 | Refractured | Nothing — it ends the run |
Locations from the GameRant walkthrough, trophy conditions from the 100% Guides trophy guide.
Boss names are spelled three different ways
Search for a boss and you will find Husk Centipede, Centipede Husk and, once, Hulk Cluster. The trophy conditions are the closest thing to an official spelling — all seven read "Defeat [boss name]". Walkthrough prose drifts from there: GameRant writes Hulk Cluster and Centipede Husk, and the 100% Guides vault guide writes Radiant Host for the same boss the trophy calls Radiation Host.
Trophy popups are how the game spells these itself, so check checklists against the trophy column above, not the name in whatever walkthrough you have open.
Boss by boss: what to bring
Husk Cluster — Habitation Sector. The first real wall of the game and the one fight you cannot walk away from, because the shuttle entrance behind it is your route into Factory East. You arrive with the Riot Breaker and little else, so keep the Pulse Gun on the grunts.
Husk Centipede — Reactor B2. You get here by activating the Power Cells, riding to B3, clearing the lockdown encounter and hitting the Security System Terminal, then riding back to B2. Without that terminal the security doors stay shut and B2 is a dead end. It is the fight most players lose, because the Reactor is where enemy density first outruns you.
Restoration Pods are the save points, the respawn points and the only place you swap Suit Mods. Rest at one before every boss door on this list — see how Suit Power and Suit Mods work.
Security Sentinel — Factory West. Three tools stand between you and the boss floor, in order: the Mechanical Crank from Maintenance extends a bridge, the Scanner finds three Energy Nodes behind a door, an Explosive Charge blows the weak floor. The Sentinel drops right behind the Factory West SCU, so clearing it is also that SCU override.
Drowned Husk — Waterworks. You need the Operations Key first, and it sits on a workbench across the moving water. The boss is what makes the water controllable — the terminal past it stops the flow permanently, unblocking the route to the Containment Sector.
Radiation Host — Containment Sector, Isolation Cistern. The only boss with an equipment gate. The Radiation Protection Suit Mod is not in the Containment Sector; it sits in Factory East B2 behind the Basement Keycard, and you fit it at a Restoration Pod before going back in. The room also hands you the Grappling Hook. Without the mod you take radiation damage the whole approach — see the Suit Mod guide.
Failed Experiment — Neural Chamber. The Incinerator is found in this same area, and the Parasitic Growth on the north wall is what it is for. Burn it, follow the path, and the boss is at the end. The Neural Chamber Access card is in the room to the west.
Fractured Being — Lower Levels. No new tool, no new puzzle. Backtrack to the door the Neural Chamber Access card opens, pass the Save Room on the east side, and go north.
The two optional bosses
Both sit off the critical path, and both carry a Vault Key — which is why the key count does not match the boss count.
- Brood Keeper, Ventilation Tunnels. Explosive Charge on the weak wall right of the easternmost tunnel entrance from Factory East, climb to F2, pull the ladder down to F3, and clear the ambush for the Ventilation Maintenance Key. Then use the Grappling Hook to drop the ladder bottom-left of F3, press the switch inside, head back to F1 and climb the ladder in the circular area. Trophy: Exterminator. Key: #7.
- Morgue Dweller, Infirmary. Burn the Parasitic Spire in the right-side labs on F1 in the Lower Levels for the Infirmary Key, then take the lift right of the Habitation Sector shuttle. Grab the Restricted Access Keycard on F1, go down to B1, and the boss is on the right of that floor. The Particle Disruptor sits just past it. Trophy: Dweller Dislikes Smoke. Key: #8.
The second Husk Centipede fight
Its trophy is separate from the story one. You beat Husk Centipede a second time by climbing into the Reactor Pool after you drain it — the circular room of glowing blue liquid in the Reactor area.
Draining it is a Waterworks errand, not a Reactor one. With the Grappling Hook you flip the switch in the room left of B3, the switch on the right side of the circular structure near the top of B3, and the pump console on the eastern side of B3. Past the pump you climb down, blast a wall at the north dead end with an Explosive Charge, then take the top-right door of B3 to open an Energy Node door and survive an ambush. The switch at the end of that path drains the pool.
Waste Management is for draining the pool. Don't Come Back is for killing Husk Centipede once the pool is empty. Doing the second without the first is not possible, so take them in that order.
What each boss drops
The seven story bosses yield five Vault Keys, one keycard and nothing else — Fractured Being drops no collectible. The other three of the eight keys come from the second Husk Centipede fight and the two optional bosses. Which Suit Mod sits in which Vault is in the vault and vault key guide.
Which boss trophies are the rarest
On PSNProfiles' trophy list, Shuttle Station Cleared is the only boss trophy in the Rare tier. Sentinel Shutdown, Giantslayer, Radiation Contained, Specimen Terminated and Refractured are labelled Ultra Rare, and the optional fights — Exterminator, Dweller Dislikes Smoke and Don't Come Back — are the rarest of the lot. That ranking holds, but percentages move daily, so read current numbers off the trophy list rather than trusting a figure quoted anywhere, including here.
FAQ
Are any End of Abyss bosses missable? No. The 100% Guides guide lists zero missable trophies, and each of the seven sits on the critical path or behind a key you need anyway. The one documented way to lose trophies is activating cheat codes from the Logbook.
Do I need a Suit Mod before a boss? One, and only one: Radiation Protection before the Radiation Host. Everything else is reachable with the weapon you already have.
Can I fight Husk Centipede twice? Yes, optionally. The first is the story fight in Reactor B2. The second is in the drained Reactor Pool and earns Don't Come Back plus Vault Key #6.
Why does my boss checklist not match the guide names? Because walkthroughs transcribe the names loosely. Use the trophy conditions, which are the game's own spelling.
Related
More End of Abyss Guides
Every End of Abyss area and floor in one table: Outer Sector, Habitation, Factory East and West, Waterworks, Containment Sector, Lower Levels.
End of Abyss PC is Epic Games Store only. How to install and run it, which settings actually exist, and the answer on co-op and Steam.
End of Abyss scored 8, 90 and 6 across Shacknews, GamingTrend, GameSpot and IGN. What they all agree on, where they split, and who should skip it.
The End of Abyss scanner is on the d-pad and it gates progression: it reveals Energy Nodes that open locked doors, hidden paths, and the map itself.
The exact End of Abyss progression chain: three power cores, three SCU overrides, the Central Elevator to Lower Levels, and every keycard on the way.
End of Abyss never explains itself. Who Cel is, why she was sent underground, and what the parasite, the crew and the notes actually tell you.
Missing a lever you already walked past? End of Abyss buries progression in dark multi-floor rooms. A symptom-to-fix table for the common softlocks.
How End of Abyss Suit Power works, where Energy Cells raise it, and which Suit Mod you need to survive radiation. The gate is your suit, not your damage.