👻 Boss Guide Updated March 20, 2026

The Hollow King — Boss Guide

The Hollow King is the fourth boss and the one that teaches a mechanic unique in the entire game: ghost immunity. During its translucent phase, most damage sources are reduced to zero. Only physical-hit damage bypasses immunity. Players who built around Venom Bow burst arrive here to discover their primary DPS source does nothing for 6–8 seconds of every immunity cycle. This guide explains exactly what works, what doesn't, and how to maintain damage output through every immunity window.

The Hollow King

Boss 04 · Map: Sunken Ruins / The Vale · Unlocked after Deep Forest

Difficulty

3Phases

GhostImmunity Type

PhysicalBypass Damage

SpectralPhase 2 Adds

Contents

The Ghost Immunity Mechanic — How It Works
What Bypasses Immunity — Complete List
Pre-Pull Checklist
Phase-by-Phase Breakdown
Recommended Build
Common Mistakes

The Ghost Immunity Mechanic — How It Works

The Hollow King periodically enters a translucent ghost state during which it glows with a faint blue-purple shimmer. While in this state, most damage sources are reduced to zero. Abilities that deal damage via magical or energy effects — Wand of Lightning chains, Venom Bow poison burst, Ban Hammer's damage component — all register as zero or near-zero during immunity. The immunity is not total; certain physical-impact sources still land. The immunity phase lasts approximately 6–8 seconds and cycles every 18–22 seconds.

The visual tell is clear and readable: the Hollow King's body becomes semi-transparent and emits visible spectral particles. The moment the translucency begins, your damage output will visibly drop. This is expected. The question is whether you have physical damage sources equipped to fill the gap.

👻 The "PLEASE HOW DO I KILL THE GHOSTS" Problem

This boss fight generated the most-upvoted confused comment in the Tangy TD Steam community: "PLEASE HOW DO I KILL THE GHOSTS??? I don't do any damage, do I need to buy a special sword or something?" The answer is no special sword — you need Bleed Lance on the Defender and Stone Hammer also on the Defender. Both deal physical-typed damage that bypasses the immunity. Venom Bow does not bypass it. Wand of Lightning does not bypass it. Physical hits do.

What Bypasses Immunity — Complete List

Damage source behaviour during Hollow King ghost immunity phase

Bleed Lance DoT

✓ BYPASSES

Stone Hammer hit

✓ BYPASSES

Defender base attack

✓ BYPASSES (reduced)

Archer base arrow

✓ BYPASSES (reduced)

Counterattack reflect

✓ BYPASSES

Venom Bow burst

✗ BLOCKED

Wand of Lightning

✗ BLOCKED

Bleed Chance (Archer node)

✗ BLOCKED

Ban Hammer stun damage

✗ BLOCKED

Pumpkin King golem

✗ BLOCKED

The practical consequence: Bleed Lance on the Defender is mandatory for this fight. It is the highest single-source DPS during immunity phases — 5% max HP per second ticking continuously regardless of the boss's immunity state. Stone Hammer on the Defender adds knockback hits that also land during immunity. The Venom Bow Archer is essentially on standby during immunity windows; the Defender is carrying the DPS.

✓ The Double-DPS Window

When the immunity drops, both Bleed Lance's ongoing tick AND Venom Bow's accumulated stacks all land simultaneously. The 2–3 seconds after immunity drops are the highest burst DPS window in the fight — Venom Bow stacks that built up during immunity fire their burst immediately as immunity ends, while Bleed Lance continues ticking. Keep the Archer attacking during immunity to pre-stack Venom for this transition burst.

Pre-Pull Checklist

Bleed Lance equipped on Defender — non-negotiable. If it hasn't appeared in the shop, Cauldron your weakest Epic for a reroll before pulling.
Stone Hammer equipped on Defender — second physical damage source. Knockback also controls wave enemy positioning during triple-path management.
Confirm all three paths are clear — Sunken Ruins has up to three simultaneous paths by Wave 7. Stray enemies during the boss fight route directly to the base on the unguarded paths.
Defender at full HP, Healer at correct lateral position — standard pre-pull requirement.
Understand the immunity visual — translucent blue-purple shimmer = immunity active. The first time you see it during the pull, don't panic. Your Venom damage dropping to zero is expected.

Phase-by-Phase Breakdown

Phase 1 — Hollow Court (100% → 70% HP)

Immunity cycle active · No adds · Pace: Moderate

Standard engagement with immunity cycling every 18–22 seconds. The Hollow King uses relatively predictable melee attacks and a slow soul projectile during active phase. During immunity, maintain Archer attacks to pre-stack Venom. When immunity drops, the stack burst fires immediately — watch for the burst proc the moment the boss becomes opaque again.

Soul Strike

MODERATE

A slow-moving spectral projectile fired at the Defender. Tracks the Defender's position slowly. Has a wind-up telegraph (boss raises hand). Dodge by moving the Defender sideways briefly — the projectile continues to the old position.

Hollow Grasp

MODERATE

Tell: hand reaches forward for 0.7s

A melee grab that pulls the Defender one tile closer to the boss. Repositions the Defender out of optimal Healer coverage briefly. Not lethal; the Healer needs to follow. Stone Hammer's knockback procs during the Grasp sequence push the boss back simultaneously.

Ghost Phase

IMMUNITY

Boss enters translucent state. Blocks all non-physical damage. Continues Soul Strikes during immunity. Bleed Lance ticks continue. Keep the Archer firing to pre-stack Venom for the drop.

Phase 2 — Spectral Court (70% → 35% HP)

Adds summoned · Immunity frequency increases · Pace: Elevated

At 70% HP the Hollow King summons spectral minions — smaller ghost enemies that orbit the boss and can target your towers directly. The adds have the same ghost immunity as the boss during the boss's immunity phase. When the boss is immune, the adds are immune. When the boss is vulnerable, the adds are vulnerable. Focus the boss; the adds die with the boss automatically.

Spectral Minions

HIGH PRIORITY

2–3 small spectral adds orbit the boss and periodically charge nearby towers. They deal moderate damage but have low HP — they die instantly to any physical hit that lands during their non-immunity window, and die automatically when the boss dies. Do not redirect primary DPS to adds. Only address them if they're reaching the Archer or Healer directly.

Hollow Aura

HIGH

Tell: expanding ring animation from boss position

A ring AoE that expands outward from the boss's position and deals significant damage to all towers it passes through. The ring expands slowly enough to sidestep — throw the Defender backward one tile when the ring begins expanding. The Archer and Healer are typically outside the ring's range from their standard positions.

Ghost Phase (accelerated)

IMMUNITY

Immunity cycles now fire every 14–16 seconds instead of 18–22. The uptime of non-immune state is shorter. Bleed Lance's continuous tick is increasingly the primary DPS source in Phase 2.

III

Phase 3 — Hollow Reign (35% → 0% HP)

Enrage · Rapid immunity · Wail attack

At 35% HP the Hollow King enrages. Immunity cycles become very frequent — the boss may spend more time in ghost form than vulnerable form. The Wail attack is added: a channelled scream that deals sustained damage to everything in a forward cone. Bleed Lance is now your primary DPS source for the entire Phase 3. The key is patience — wait for vulnerability windows, fire the Venom burst, return to Bleed Lance during immunity, repeat until the boss dies.

Hollow Wail

LETHAL (Archer/Healer)

Tell: boss opens mouth wide, 0.8s before beam fires

A sustained damage cone fired forward. Lethal to non-Defenders caught in the cone. The Defender can survive it with Iron Fortress shield active. The Archer and Healer must be out of the forward arc — diagonal positioning keeps both safe. If the Defender's Iron Fortress is on cooldown when Wail starts, throw the Defender sideways to interrupt the cone alignment.

Rapid Ghost Phase

IMMUNITY

Immunity now cycles every 8–10 seconds. Vulnerable windows are brief. Bleed Lance continuous tick is your primary DPS for Phase 3. Accept that Venom bursts will be fewer and Bleed carries the kill.

Recommended Build

Tower	Slot 1	Slot 2	Slot 3	Slot 4
🛡️ Defender	🏰 Iron Fortress Periodic shield	🩸 Bleed Lance Bypasses immunity	🪨 Stone Hammer Bypasses immunity	🔨 Ban Hammer Stun during vuln
🏹 Archer	🐍 Venom Bow Pre-stack during immunity	💚 Emerald Bow Pierce for adds	❄️ Frost Wand Slow adds	🥽 Ultra Vision Goggles Range for safety
✨ Healer	💫 Healing Circle Core regen	🔵 Shield Orb Burst absorption	👟 Speed Boots Adds repositioning	🔮 Aura Extender Triple-path coverage

Common Mistakes

Equipping only Venom Bow and no Bleed Lance before this fight

Venom Bow deals zero damage during immunity phases. A build with no physical damage source stalls completely for 6–8 seconds every 14–22 seconds. Against a three-phase boss, those immunity windows accumulate into a slow DPS loss that eventually exceeds what the build can recover.

Fix → Bleed Lance on the Defender before this boss. It is mandatory. The 5% max HP/sec tick continues through every immunity phase.

Stopping attacks during immunity windows

The visual cue of zero damage numbers appearing feels like an invitation to pause and wait. Stopping attacks wastes the Venom pre-stack window that makes the immunity-drop burst valuable.

Fix → Keep the Archer firing during immunity. The stacks build even when no burst occurs. When immunity drops, the fully-stacked burst fires immediately.

Redirecting DPS to spectral adds in Phase 2

The adds summon during Phase 2 feel threatening and look like priority targets. They have low HP and die with the boss. Every attack spent on an add is an attack not spent on reducing boss HP — which is the only thing that ends Phase 2 and stops further add summons.

Fix → Focus the boss exclusively. The adds die automatically when the boss does.

Not positioning the Archer diagonally from the boss

The Hollow Wail fires in the boss's forward facing. If the Archer is directly behind the Defender (in the boss's forward arc), Phase 3's Wail catches all three towers simultaneously.

Fix → Diagonal Archer placement from the start of the pull. Northeast of the boss when the Defender is south. The Wail cone never reaches a true diagonal.

Leaving one of the Sunken Ruins paths uncovered during the boss fight

Sunken Ruins has triple paths active in late waves. Stray enemies from uncleared wave segments — or new spawns if the map has residual spawn timers — can route through unguarded paths during the boss fight and reach the base directly.

Fix → Full wave clear before approaching the boss. After the pull, position a Defender at the secondary path entrance even during the boss fight.

Next Boss — The Iron Warden

Boss 05 is The Iron Warden on Irongate. It introduces siege engines — environmental hazards that deal periodic AoE damage to your tower positions. The immunity mechanic does not carry over; all damage types work normally. But the Iron Warden has the highest armour value of any non-final boss, meaning flat damage is again suppressed. See the Iron Warden Guide.