Balgorath: the bullet-hell Gatekeeper
The fourth Gatekeeper does not chase you. It does not need to. It fills the room with patterns and waits for you to run out of space.
Stay close for the beam sweep, jump the ground rings instead of strafing, and shoot only in the gap between patterns, because its projectiles eat your bullets. Kill the tentacle within four to six seconds when it grabs the Corestone.
Balgorath is the fourth Gatekeeper and the reason Depth 4 is a wall. A bullet-hell fight: the boss mostly does not move, and instead fills the arena with rotating walls, expanding rings and orbs that burst into pillars.
The single mechanic that changes everything is that its projectiles block your shots. Holding the trigger through a pattern does nothing, because your bullets stop at the wall of energy in front of the boss.
Attack set, phase by phase
The fight is split into three phases, and each phase adds attacks. A Corestone phase sits between them, where the boss becomes invulnerable and a tentacle grabs the Corestone.
| Phase | Attacks | Counter |
|---|---|---|
| 1 | Energy Wave, Spiral, Quad Starburst | Jump the ring, walk the spiral gap, dodge one orb only |
| 2 | Adds Quad Beams, Rising Waves | Get close for beams; do not jump the second ring |
| 3 | Adds Barrage | Keep moving, the impact zones linger |
Attack names are the wiki's placeholder labels, checked 2026-11-15. The boss is immune to stun during all of its attacks, with half-duration stun possible in the gaps.
Energy Wave and Rising Waves
Energy Wave is a ring of purple energy that slams out from the boss and travels at about 17.5 metres per second. Jump it. It sometimes fires a second slam straight after, so land ready.
Rising Waves sends three rings at increasing heights, 3.25 metres apart. The second ring passes just above your head, and the counter is to not jump. This is the attack that kills people who learned to jump on the first ring and kept doing it.
Spiral and Quad Starburst
Spiral fires pillars from the boss's eyes while rotating one way, then reversing. There are eight shots per volley, a 0.3 second gap between pillars, and blades that move at 8.5 metres per second and stand 18 metres tall.
Quad Starburst sends four orbs out to the edges of the cave, where each detonates into four beams that travel at 90 degrees. The key detail is that each set always moves into the next, so dodging one set is enough. Focus on one orb and ignore the other three.
Quad Beams
In phase 2 the boss pulsates purple, spins, then fires a beam from each eye and rotates it about 250 degrees. The counter is counter-intuitive: get close. The closer you are, the less distance you have to cross to stay ahead of the sweep.
Corestone routine
Every third of health, Balgorath rises out of the rift and stops firing. A wave of Core Spawn keeps spawning, and one tentacle burrows up to grab the Corestone.
| Detail | Value |
|---|---|
| Tentacle health | 500 |
| Spawn interval | Every 4 to 6 seconds |
| Cannot grab within | 8 metres of the rift |
| Kill it and | The Corestone drops or is flung free |
| Finish the phase | Throw the Corestone into the rift |
Values from the community wiki, checked 2026-11-15. The tentacle cannot grab a Corestone that is close to the rift, which is why the throw should happen from close range.
Why 3.6% is the number
The achievement is called Balgorath Annihilator and 3.6% of players have it. Three things make this fight different from the first three Gatekeepers.
First, the shield behaviour punishes the default strategy. Every earlier boss rewards sustained fire, and this one makes sustained fire useless during patterns.
Second, the fight is long enough that Corestone discipline decides it. Three Corestone phases means three chances for one person to die holding the stone.
Third, Rising Waves breaks the habit the earlier attacks teach. A player who has spent three phases learning to jump has to unlearn it for one specific ring.
Packing for Depth 4
- A team, not a solo run. The Corestone routine needs someone free to kill the tentacle.
- A Threat Level one below your comfort. Depth 4 on Threat 2 is a fair fight; on Threat 4 it is a donation.
- Flux Quartz. A run that reaches the boss floor with a bad draft is a run you can still save with a reroll.
- The habit of stopping your fire. Shooting into a pattern is worse than not shooting.