Abyssus Secret Boss Guide

Aug 23

The secret boss in Abyssus is unlocked by using a Deep Water modifier that grants bosses additional skills. This extra phase appears after what seems like the normal fight, but it quickly turns into one of the toughest DPS checks in the game. Many builds that shred everything else fail here, making it one of the hardest challenges in Abyssus.

How to Unlock the Secret Boss

Add the Deep Water modifier that says “boss got additional skill” at your basecamp.
The extra phase usually appears around Deep Water level 10 or higher.
After you defeat the boss, the hidden phase begins automatically.

Secret Boss Mechanics

The boss dives underwater and becomes immune during its charge-up.
Its HP bar sometimes looks empty while it is submerged, but the bar comes back when it resurfaces.
Once it returns, you have a short window to burn through its health before it becomes immune again.
The final 25 percent is the hardest part. If you cannot melt it in time, the boss will enrage and wipe you out instantly.

Best Builds and Strategies

Blood Blessing Primary: This blessing grants max HP on quick kills, letting you sustain through adds and damage.
Ice Secondary: Strong against bosses and useful for slowing adds, but avoid the slide blessing as it can bug enemies.
Turrets with Barrier or Shadow: Great for stacking extra damage procs and giving you more uptime.
Disc Thrower with Fire Primary and Ice Secondary: High burst and consistent damage across phases.
Shotgun or Saw builds: Can work if supported by the right blessings, but lightning has been tested and found weak for this fight.

Tips for Beating the Final DPS Check

Save cooldowns and abilities for the last quarter of the fight.
Drop turrets and barriers right before the boss resurfaces to maximize uptime.
Position yourself close but safe, since every second of DPS matters.
If you see the HP bar disappear mid-fight, wait for the resurface rather than wasting resources.

Known Bugs and Issues

The HP bar may appear empty underwater even though the phase is not over.
Sometimes the boss stays immune after resurfacing, making it unwinnable.
Ice blessings with sliding effects can push enemies into walls, causing glitches.
Revives may not work if the boss triggers its instant kill during enrage.

Final Blurb

The Abyssus secret boss is a brutal test of damage and survival. Unlocking it with the Deep Water modifier reveals one of the most punishing fights in the game, capped by a final DPS check that destroys unprepared builds.

Use high burst setups, time your cooldowns, and be ready to burn through the last quarter fast if you want to clear this hidden challenge.

FAQ

How do you unlock the secret boss in Abyssus?

Enable the Deep Water modifier that gives bosses additional skills. The hidden phase appears after the normal fight.

What makes the secret boss so difficult?

The final 25 percent is a strict DPS check. If you cannot burn it down before it becomes immune, the boss enrages and wipes you.

What builds work best against the secret boss?

Blood Blessing for sustain, Ice Secondary for control, turrets with barrier or shadow for burst uptime, and Disc Thrower with fire and ice for high consistent damage.