End of Abyss bosses: every fight, the weapon it wants and what it drops

Two things decide a boss fight in this game and the game tells you neither in advance: which weapon the fight actually wants, and whether killing it pays anything beyond progress.

Here is the whole list with both, plus the honest length of each fight, read off uncut footage rather than a highlight cut.

Every boss, with the drop and the weapon

Boss	Length	Weapon the fight wants	What it pays
Husk Cluster	2:20	Pulse Gun	A Vault Key
Centipede Husk	3:12	Pulse Gun, movement	progress
Radiation Host	2:55	Pulse Gun	A Vault Key
Security Sentinel	3:57	Rifle, then Pulse Gun	progress
Drowned Husk	3:49	Consumables, Pulse Gun	progress
Brood Keeper	2:19	Incinerator, 150 rounds	Exterminator trophy, 5 XP
Severed Centipede Husk, secret	3:39	Incinerator	Don't Come Back trophy
Morgue Dweller	6:18	Pulse Gun alone	A new database entry
Fractured Being, final	7:26	Rifle, then Pulse Gun	A new database entry

Two of the nine drop a Vault Key, the Husk Cluster and the Radiation Host, which makes them the two worth killing for the reward rather than for the road. Nothing stops you walking out of the room without it, since the key lies on the floor where it fell.

Two of the nine want the Incinerator rather than the Pulse Gun, and this is the single biggest difference between a fight that takes two minutes and one that takes six. The Brood Keeper goes down in 2:19 with it and the counter reads 00 by the end.

The one most completion runs miss

The Severed Centipede Husk is a secret optional boss, so the game never points you at it and most runs finish without meeting it. It pays the Don't Come Back trophy, which is why an optional boss nobody mentioned is the usual reason a completion run comes up short right at the end.

It brings a second health bar. Partway through there are two on screen at once, and if you have settled into trading damage with one target that is the moment it stops working. The moveset reads as familiar until then, since this is the severed version of a boss you have already fought.

What each fight is actually about

The Husk Cluster is the first boss and the cluster is not the problem. It sits there as a large mass and spawns smaller husks around the arena. The adds are the threat and the cluster is the timer. Standing still to shoot the big target is how most first attempts end. Killing it also opens the shuttle network, so this one fight ends the game's no fast travel period.

The Centipede Husk takes away your options. A circular grated arena with red glowing points around the edge, no corner to retreat into and no cover to break line of sight with, so movement is the whole defence. Both consumable slots read zero for most of our run, which is worth seeing: it is winnable on the unlimited Pulse Gun and footwork alone.

The Radiation Host is a visibility problem, and it floats. Thick green radiation fog fills the arena and never lifts, and the Host hangs in the air rather than walking the ground with you, so shooting where you would normally shoot misses. The circular platform has a triangle marked on it, which is the one piece of ground you can read through the haze.

The Security Sentinel is a machine rather than a husk, a four legged walker with a glowing core in a flooded industrial room. The boss bar barely moves through the first half, and that is the honest shape of it: four minutes is long enough to empty the rifle twice, so treating it like a short fight is how it goes wrong.

The Drowned Husk is attrition in water. Green murk, standing water and grating underfoot make reading an incoming attack harder than in any dry fight on this game. Our health bar is down to roughly a quarter by the last stretch. This is the clearest argument in the game for turning up stocked.

The Morgue Dweller is six minutes on the Pulse Gun with the rifle slot empty, fought in a room walled with corpses stacked into mounds on every side. The floor is the only clear ground, so the edges are scenery you cannot use. The game saves straight after the kill.

The Fractured Being does not stay the same thing. The final boss opens as a low reddish mass dragging tentacles along the ground, then rises into something much larger and multi limbed with tendrils crossing the arena. Anyone who settles into a rhythm against the first form gets caught by the second. Seven and a half minutes is the real length, and by the end the rifle is dry and the Pulse Gun finishes it.

Our final boss video carries on past the kill into the story, so stop at the kill if you want the ending kept for your own run.

On the weapon names

The starting weapon is the Pulse Gun and it carries unlimited ammo, read off the weapon card with the infinity symbol beside it. Some of our earlier guides call it "the pistol", which is what it looks like rather than what the game calls it. The slot above it holds whatever you brought, the Security Rifle or the Incinerator, and that slot is the only ammo you are actually managing.

Every fight above is filmed complete and uncut, start to kill, because the openings and the long stretches between them are the part you need to see.