Boss Strategy Guide

Each Abyss region ends with a Domain Boss gate that must be defeated to progress. This guide covers actual boss element resistances (from game data), optimal build picks, gem adjustments, and danger mechanics for every region boss.

Region Overview

#	Region	English Name	Boss Gate Depth	Boss	Element Weakness
1	浅层深渊	Shallow Abyss	—	None (tutorial)	—
2	低语回廊	Whispering Gallery	Depth 55	Guttorm	None (55/55/55/55)
3	呢喃阶梯	Murmuring Steps	Depth 101	Ifrit	Ice (30)
4	绝望中庭	Courtyard of Despair	Depth 150	Fafnir	Ice (25), Fire (30)
5	极昼止境	Polar Day's End	Depth 202	Chimera	Poison (10)
6	极夜幽径	Polar Night Path	Depth 252	Grimhild	Poison (35)
7	幽邃小道	Dark Passage	Depth 300	Ortiz	Fire/Ice/Lightning (40)
8	深渊核心	Abyss Core	Depth 300+	Keeper + Prometheus	All high (55-60)

How to read resistances: Lower number = more damage gets through. Poison resist 10 means the boss takes almost full poison damage. Resist 55 means roughly half is blocked.

Boss Element Resistances (Actual Game Data)

Boss	Fire Res	Ice Res	Lightning Res	Poison Res	Best Element
Guttorm	55	55	55	55	Physical (bypass all resist)
Ifrit	50	30	40	40	Ice or Poison
Fafnir	30	25	35	35	Ice or Fire
Chimera	25	25	25	10	Poison (by far)
Grimhild	50	50	55	35	Poison
Ortiz	40	40	40	50	Fire / Ice / Lightning (tied)
Keeper of Fire	40	40	55	50	Fire / Ice
Evil God Prometheus	55	55	60	55	Physical (all resists very high)

Key insight from the data: Poison Archer is the best DPS choice for the majority of bosses (Chimera, Grimhild especially). The community meme that "Poison is slow" ignores that bosses 5 and 6 have 10 and 35 poison resist respectively — poison melts them.

Region 1 — Shallow Abyss (Depths 1–9)

No boss. Tutorial area. Focus on learning combat basics and unlocking all 3 hero slots.

Region 2 — Echo Corridor: Guttorm

Depth 55 | All resists 55 | Physical boss

Guttorm has perfectly balanced 55% element resistance across the board. No element has an advantage — physical damage or raw ATK scaling is best.

Danger Mechanics

Cleave Attack: 180-degree frontal swing. High physical damage. Only the tank should be in front.
Ground Slam: AoE around Guttorm. Brief telegraph — moves back slightly before slamming.
Poison Trap (adds): Guttorm spawns poison trap objects (40 all resist). Ignore them unless they stack.
No enrage timer. You can take as long as you need.

Optimal Builds

Slot	Best Pick	Build Guide	Why
Tank	Taunt Warrior	Rock Dragon card	Only viable tank for boss aggro control
Healer	Healer Mage	Boar King card	Keep the tank topped off
DPS	Quintuple Archer	Fear of Fear card	Physical burst ignores Guttorm's 55 element resist

Alternative DPS: Multi-Shot Archer if you need AoE for trap cleanup, or any DPS really — Guttorm is a basic gear check.

Gem Adjustments

None needed. Use your standard PvE gem setup. If your tank is dying, upgrade their Emerald (HP) gems.

If you're stuck: The issue is almost always gear level, not strategy. Farm more floors for equipment upgrades.

Region 3 — Murmuring Steps: Ifrit

Depth 101 | Weakest to Ice (30) | Fire boss

Ifrit has 50 fire resist but only 30 ice resist. Ice Mage is the clear winner here.

Danger Mechanics

Fireball Barrage: Launches 5 fireballs at random team members. Moderate fire damage each.
Flame Pillar: Drops a fire zone on the ground. Continuous fire damage if you stand in it.
Immolation Aura (at 50% HP): Permanent fire aura deals fire damage to melee characters every second.

Optimal Builds

Slot	Best Pick	Build Guide	Why
Tank	Taunt Warrior	Rock Dragon card	Must survive Immolation Aura melee fire damage
Healer	Healer Mage	Boar King card	Resist shred helps strip Ifrit's fire resist for the team
DPS	Ice Mage	Silver Knight card	Ifrit has only 30 ice resist — Ice Mage deals ~40% more damage than other elements here

Alternative DPS: Poison Archer (40 poison resist is decent), or SP Hakuya for perma-freeze + ice burst. Avoid all fire DPS — Ifrit has 50 fire resist.

Gem Adjustments

Swap	From	To	Why
Tank Amulet S3	Emerald (HP)	Diamond (All Resist)	Fire resist reduces all of Ifrit's damage
Healer Amulet S3	Jade (HP Regen)	Diamond (All Resist)	Healer needs to survive Fireball Barrage

Common mistake: Bringing a Fire Mage to Ifrit. 50 fire resist makes your fire damage nearly worthless.

Region 4 — Courtyard of Despair: Fafnir

Depth 150 | Weakest to Ice (25) | Dragon boss

Fafnir has the lowest ice resist of any boss at 25, and also low fire resist (30). Dragon Breath is a fire+physical combo, so stack fire resist on your tank.

Danger Mechanics

Tail Sweep: Hits all melee characters behind Fafnir. Massive physical damage.
Dragon Breath: Cone of physical + fire damage. Tank absorbs this.
Crystal Missiles (at 30% HP): Homing projectiles dealing pure damage (ignores DEF). This is the DPS check.

Optimal Builds

Slot	Best Pick	Build Guide	Why
Tank	Taunt Warrior	Rock Dragon card	Stack Sapphire DEF gems for physical survival
Healer	Healer Mage	Boar King card	Constant healing required for Dragon Breath
DPS	Ice Mage	Silver Knight card	25 ice resist = maximum damage throughput

Alternative DPS: Poison Archer (35 poison resist — solid), SP Hakuya (ice burst + freeze = dream matchup), or Fireball Chain Mage (30 fire resist is workable).

Gem Adjustments

Swap	From	To	Why
Tank Armor S3	Emerald (HP)	Sapphire (DEF)	DEF directly mitigates Fafnir's physical burst
Tank Amulet S2	Emerald (HP)	Sapphire (DEF)	Stack as much DEF as possible for Tail Sweep

DPS check: If Crystal Missiles overwhelm your team, your DPS is too low. Upgrade DPS weapon gems.

Region 5 — Polar Day: Chimera

Depth 202 | Weakest to Poison (10) | Multi-element boss

The data tells the real story: Chimera has only 10 poison resist — the lowest resist of any boss against any element in the entire game. Poison Archer absolutely destroys this boss.

Danger Mechanics

Tri-Element Breath: Combined fire+ice+lightning breath in a wide cone.
Poison Cloud: Drops a poison zone. 3 stacks of DoT.
Element Shift: Every 20 seconds, Chimera changes its primary element. Single-element resist stacking is a trap.
Frenzy (at 25% HP): Attack speed doubles, all elements active simultaneously.

Optimal Builds

Slot	Best Pick	Build Guide	Why
Tank	Taunt Warrior	Rock Dragon card	Diamond gems for All Resist against multi-element
Healer	Healer Mage	Boar King card	Resist shred amplifies your poison even further
DPS	Poison Archer	Forest Queen card	10 poison resist = Chimera takes nearly full poison damage. No other boss is this weak to any element.

Alternative DPS: SP Morpheus (if you have him, this is the fastest Chimera kill in the game — infinite poison stacking vs 10 resist). Fire/Ice/Lightning DPS all work too (25 resist each), but poison is objectively ~2.5x more effective.

Gem Adjustments

Diamond (All Resist) gems are mandatory for tank and healer — Chimera attacks with every element.

Swap	From	To	Why
Tank Amulet all 3	Any	Diamond (All Resist)	Multi-element damage requires broad coverage
DPS Amulet S3	Any	Diamond (All Resist)	Survive Tri-Element Breath splash
Healer Amulet S3	Jade	Diamond (All Resist)	Stay alive during Frenzy phase

Pro tip: If you've been building Poison Archer as your F2P main, Chimera is your victory lap. The 10 poison resist makes this the easiest boss for poison builds despite being "Region 5."

Region 6 — Polar Night: Grimhild

Depth 252 | Weakest to Poison (35) | Mixed damage + enrage timer

Major difficulty spike. Grimhild has high fire/ice resist (50/50) and very high lightning resist (55), but only 35 poison resist. She also has an enrage timer — the first boss that demands both survival AND DPS.

Danger Mechanics

Soul Drain: Targets lowest HP% hero. Drains 30% current HP over 3s. If completed, Grimhild heals the same amount.
Dark Wave: Room-wide AoE. Pure damage (ignores DEF). Unavoidable.
Enrage Timer (90 seconds): +100% ATK, +50% ATK speed, +100% DMG. Stacks every 30s after enrage.
Phase 2 (at 50% HP): Summons 3 puppet types (格莉希尔德的傀儡). Puppets 1 & 2 have only 10 all resist — easy to kill. Puppet 3 has 40/40/65/40 resist (strong vs lightning). Kill puppets or they heal Grimhild.

Optimal Builds

Slot	Best Pick	Build Guide	Why
Tank	Taunt Warrior	Rock Dragon card ★3+	Must survive Dark Wave — raw HP matters more than DEF here
Healer	Healer Mage	Boar King card	Out-heal Soul Drain + resist shred for DPS
DPS	Poison Archer	Forest Queen card	35 poison resist is the lowest — poison DPS beats the enrage timer

Alternative DPS: Quintuple Archer with Fear of Fear (physical burst bypasses 50/50/55 element resist), SP Morpheus (infinite poison stacking melts Grimhild). Avoid lightning builds (55 resist) and fire/ice (50 resist each).

Gem & Card Requirements

★4 card minimum on your DPS. ★3 cards cannot meet the enrage DPS check.
DPS weapon gems Lv4 minimum.
Tank Emerald gems Lv4+ — Dark Wave hits through DEF, raw HP is the only defense.
All bench pet passives Lv3+.

This is where F2P players hit the wall. Grimhild requires genuine investment. Priority: (1) DPS weapon gems to Lv4-5, (2) ★4 card on DPS, (3) pet passives to Lv3. These three changes are usually enough.

Region 7 — Dark Passage: Ortiz

Depth 300 | Equal fire/ice/lightning resist (40) | Poison-resistant (50) | Debuff-heavy

Ortiz is the first boss where poison is actually bad (50 resist). Fire, ice, and lightning are equally effective (40 each). Pick whichever element you have the best gear for.

Danger Mechanics

Curse Mark: Stacking debuff (-5% ATK per stack, max 20 = -100% ATK). Applied every 5s to highest-DPS hero.
Shatter Armor: -50% DEF for 10s on the aggro target (your tank).
Void Zone: Silences heroes inside (no skills for 3s).
Phantom Clones (奥尔蒂丝的幻影): Two phantoms with 40 all resist. Must be killed.
Soul Siphon (at 40% HP): -2% max HP/sec for all heroes. Hard enrage.

Optimal Builds

Slot	Best Pick	Build Guide	Why
Tank	Taunt Warrior	Rock Dragon card	Extra Sapphire to survive Shatter Armor's -50% DEF
Healer	Healer Mage	Boar King card	Resist shred + heal through Soul Siphon
DPS	Ice Mage or Quintuple Archer	Silver Knight / Fear of Fear	40 element resist — any non-poison element works. Physical burst front-loads before Curse Mark stacks.

Alternative DPS: Fireball Chain Mage (40 fire resist = same as ice), Whirlwind Warrior (lightning at 40 resist + AoE clears phantoms), SP Hakuya (freeze + burst). Avoid Poison Archer (50 resist — worst matchup for poison in the game).

Strategy

The fight is a race. Curse Mark reduces your DPS over time. You need:

Maximum burst DPS in the first 30 seconds (before Curse Mark cripples output)
Tank survivability through Shatter Armor (stack extra Sapphire DEF)
Enough healing to sustain through Soul Siphon while DPS finishes

Milestone: Defeating Ortiz unlocks the Peak Level system — hero and pet level cap increases to 100. This is a massive power spike.

Region 8 — Abyss Core: Keeper of Fire + Evil God Prometheus

Depth 300+ | Final boss area | Multi-stage

Prometheus

The Abyss Core is a multi-phase final boss encounter through the Fireship (火种舰):

Fireship Entrance → Fireship Core → Ash Throne

Phase 1: Keeper of Fire (火种守护者)

Stat	Value
HP Ratio	30 (massive)
ATK Ratio	1.25
DEF Ratio	1.5
Speed	7
Attack Speed	120 frames (2.0s)
Knockback	Immune
Enrage	90s — stacks every 20s

Element Resistances

Fire	Ice	Lightning	Poison	Best Element
40	40	55	50	Fire / Ice (tied at 40)

Skills

Skill	Type	Damage	Range	Cooldown	Effect
AoE Lightning Strike	Basic Attack	100% Lightning + 200% Break	AoE r=1	2.0s	25% chance Silence (3s): -30 DMG bonus, no skills
Invader Mark	Active	150% Lightning + 200% Break	ALL enemies	10s	Guaranteed hit. Applies Invader debuff: -5% DMG bonus per stack (max 5 = -25%). When removed, deals 50% bonus damage per stack. Permanent duration — lasts the entire fight.

Invader Mark is the Keeper's signature ability. Every 10 seconds, your entire team gets -5% DMG bonus (stacks to -25%). The stacks are PERMANENT and cannot be cleansed. Your DPS degrades over the entire fight.

Trap mechanic: When Invader Mark stacks are removed (e.g., by death), the removal deals 50% bonus damage per stack. Dying with 5 stacks means taking massive bonus damage on resurrection. Don't let heroes die with high stacks.

Optimal Builds (Keeper)

Slot	Best Pick	Why
Tank	Taunt Warrior or Shield Wall Warrior	Shield Wall's DR is valuable for sustained multi-stage
Healer	Healer Mage	Boar King mandatory
DPS	Ice Mage or Quintuple Archer	Fire and Ice tied at 40. Avoid lightning (55) and poison (50).

Phase 2: Evil God Prometheus (邪神·普罗米修斯)

Stat	Value
HP Ratio	55 (highest in the game)
ATK Ratio	1.4
DEF Ratio	1.65
Size	3 (large model)
Speed	4
Attack Speed	120 frames (2.0s)
Debuff Resist	50 (built-in, separate from enrage)
Knockback	Immune
Enrage	90s — stacks every 20s

HP ratio 55 is 2.5x higher than any other boss. Prometheus is a massive HP sponge designed to test sustained DPS.

Element Resistances

Fire	Ice	Lightning	Poison	Best Element
55	55	60	55	Physical (all resists very high)

All resists are 55+. Lightning is worst at 60. Physical damage is the only way to fully bypass resists.

Skills

Skill	Type	Damage	Range	Cooldown	Effect
Divine Lightning	Basic Attack	100% Lightning	5 tiles (AoE r=1)	3.0s	Guaranteed hit. 100% chance Divine Punishment: -35% DMG resist (stacks 3) for 5s
Surge	Active	200% Lightning	Full screen (AoE r=15)	10–20s	Guaranteed hit. Summons 2-3 building debris. Prometheus later hurls debris for 150% damage + 3s stun.
Eruption	Active	300% Lightning	5 tiles	10–15s	Guaranteed hit. Spawns light tornado at target. Applies Paralysis (5s): no move, no attack, no skills.
Summon Keeper Clone	Phase (0–50% HP)	—	—	30s	Summons Keeper of Fire clone (HP 25, same skills including Invader Mark). Max unlimited.
Summon Fire Spreader	Phase (0–50% HP)	—	—	30s	Summons fire spreader adds. Max unlimited.
Ascension	Phase (0–25% HP)	150% Lightning	Random target	One-time	Instantly kills a random player unit. Cannot be blocked or resisted.
Collapse	Phase (0–15% HP)	Full screen lethal	All (AoE r=15)	One-time	15s charge time, then full-screen guaranteed-hit lethal AoE. This is the final DPS check.

Passive — Divine Punishment

Prometheus's basic attack applies -35% DMG resist (stacks 3 = -105% DMG resist) for 5 seconds. This means your tank takes double damage when fully stacked. The debuff refreshes every 3 seconds (his attack speed), so it's effectively permanent once combat starts.

Prometheus Summons

Summon	HP	ATK	DEF	Speed	Resists	Life	Behavior
Laser Rain (3100084)	2.5	0.8	1	0 (stationary)	55/55/60/55	10s	AoE r=2, fires 20% ATK every 0.33s. Stationary death zone.
Light Tornado (3100085)	10	1	1	4	55/55/60/55	—	Mobile, AoE r=1, 50% Lightning every 1s. Chases your team.
Keeper Clone (3100086)	25	1	1.2	7	40/40/55/50	—	Same skills as Phase 1 Keeper: Lightning AoE + Invader Mark.

Keeper Clones are the real danger. At 50% HP, Prometheus starts spawning Keeper clones every 30 seconds with NO LIMIT. Each clone applies its own Invader Mark (-5% DMG per stack). Multiple Keepers stacking Invader Marks can reduce your team's damage to nearly zero.

Phase Transitions

HP Threshold	Event
100–51%	Normal combat. Divine Lightning + Surge + Eruption.
50%	Begins spawning Keeper Clones + Fire Spreaders every 30s. The fight gets exponentially harder.
25%	Ascension — instantly kills one random hero. Cannot be prevented.
15%	Collapse — 15 second charge, then full-screen lethal AoE. Kill Prometheus before the charge completes or wipe.

Optimal Builds (Prometheus)

Slot	Best Pick	Card	Why
Tank	Shield Wall Warrior	Chrysalis	DR + party shield for surviving Divine Punishment stacks + Eruption
Healer	Healer Mage	Boar King ★4	Resist shred mandatory — 55+ resist on everything. Must out-heal Keeper clone Invader Marks.
DPS	Volley Archer	Fear of Fear ★4	Physical burst bypasses all 55+ element resists

Alternative DPS

Build	Why It Works
SP Roud	Assault stance = physical burst, no element resist issues
SP Crow	HP-scaled damage bypasses element resist entirely

Avoid element-focused builds — with 55+ all resist + cycled AoE, element DPS is crippled.

Minimum Requirements

Hero	Min Gem Level	Min Card	Notes
DPS (Weapon/Ring)	Lv7+	★4 ★4	Anything less won't beat Collapse enrage
DPS (Armor/Amulet)	Lv6+	—	Must survive Eruption + Laser Rain
Tank (all slots)	Lv7+	★4+ ★3+	Full brunt of Divine Punishment stacks
Healer (all slots)	Lv6+	★4+	Non-negotiable survival

Prometheus Strategy Summary

Physical DPS only — 55+ all element resists. Don't bring element builds.
Race to 50% HP — Keeper clones spawn after 50%. Every 30 seconds the fight gets harder. Front-load all your burst.
Kill Keeper Clones immediately — Their Invader Marks stack with the original Keeper's. Multiple -5% DMG stacks from multiple sources will destroy your damage output.
Dodge Eruption — 300% Lightning + 5s Paralysis. If your DPS gets paralyzed, you lose 5 seconds of damage against the enrage.
Survive Ascension at 25% — One random hero WILL die. Make sure it's not your only DPS. Having a second damage source helps.
15% is the final check — 15 seconds to kill Prometheus before Collapse wipes the team. Save all burst cooldowns for this window.

Final boss reality check: If you don't have Lv7+ gems, ★4 cards at max stars, and A+ quality pets, you are not ready. Farm more. There is no strategy that compensates for insufficient gear.

Drops

Drop	Rate
Ancient Legendary Equipment (Area 7 tier)	85%
Gold + Resources	Guaranteed
Equipment Recipes (x5)	Included
Artifact Stones (Tier 2)	Included
Stage Mutate Scrolls (x5)	Guaranteed

Lore

"Prometheus, the ancient god governing Thiberia, was responsible for monitoring and maintaining species evolution. At some point, Prometheus stopped uploading logs..."

"Prometheus grew tired of the endless evolution, seeking something to accelerate the shield world's evolutionary process, ultimately targeting the remnants of the ancient war — High-Energy Magic Crystals."

"Despite organisms infected by High-Energy Magic Crystals gradually losing self-control, Prometheus stubbornly believed that infecting all shield world organisms with Magic Crystals was the only path to ultimate evolution... transforming from guardian god to mad evil god."

Quick Reference: Best DPS Per Boss

This table summarizes the single best DPS choice for each boss, based on actual element resistance data.

Boss	Best DPS	Card	Element Exploit	Resist Value
Guttorm	Quintuple Archer	Fear of Fear	Physical (bypasses 55 all)	55 all
Ifrit	Ice Mage	Silver Knight	Ice weakness	30 ice
Fafnir	Ice Mage	Silver Knight	Ice weakness	25 ice
Chimera	Poison Archer	Forest Queen	Poison weakness	10 poison
Grimhild	Poison Archer	Forest Queen	Poison weakness	35 poison
Ortiz	Quintuple Archer	Fear of Fear	Physical / any non-poison	40 fire/ice/light
Keeper of Fire	Ice Mage	Silver Knight	Ice / Fire (tied)	40 ice/fire
Prometheus	Quintuple Archer	Fear of Fear	Physical (all resist 55+)	55+ all

SP Hero Picks (If Available)

Boss	Best SP Hero	Why
Chimera	SP Morpheus	Infinite poison stacking vs 10 resist = fastest kill
Grimhild	SP Morpheus	35 poison resist + unlimited stacking
Fafnir	SP Hakuya	Ice burst + freeze-lock vs 25 ice resist
Ifrit	SP Hakuya	Perma-freeze on an ice-weak boss
Prometheus	SP Crow	HP-scaled damage ignores element resist entirely
Ortiz	SP Roud	Stance switch burst before Curse Mark stacks

Boss Preparation Checklist

Boss	Min Gem Lv	Min Card	Key Defensive Gem	Key Swap
Guttorm	Lv1-2	★2	Emerald (HP)	None needed
Ifrit	Lv2-3	★2-3	Diamond (All Resist)	Drop fire DPS, bring ice
Fafnir	Lv3-4	★3	Sapphire (DEF)	Stack tank DEF for physical
Chimera	Lv3-4	★3-4	Diamond (All Resist)	Bring Poison Archer, Diamond on everyone
Grimhild	Lv4-5	★4	Emerald (HP)	Max DPS gems for enrage timer
Ortiz	Lv5-6	★4	Sapphire (DEF)	Drop poison DPS, any other element
Keeper of Fire	Lv6-7	★4	Diamond (All Resist)	Avoid lightning DPS
Prometheus	Lv7+	★4 ★4	Everything maxed	Physical DPS only