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Joint Challenge

Deep Sea Guardian — Outerplane Joint Challenge Guide

By SevihUpdated 2026-01-20
Deep Sea Guardian Joint Challenge Guide

Joint Challenge boss. The boss gains for 9 turns after using S3. Remove it with or . Increased damage from StrikerStriker, reduced from AoE attacks. Enemies without buffs take at end of boss turn.

Deep Sea Guardian

Deep Sea Guardian

WaterWaterStrikerStrikerLv.120
Immunities
Humboldt Smash

Humboldt Smash

Attacks all enemies. Inflicts Bleeding on all targets for 3 turns. If there is only 1 target, steal all buffs.

Colossal Splash

Colossal Splash

Attacks all enemies. Inflicts 2 Bleeding on all targets for 3 turns. (Ignores Immunity, Irremovable)

Architeuthis Cutter

Architeuthis Cutter

Attacks all enemies. Detonates all Bleeding stacks on the target and grants Invulnerability to the caster for 9 turns.

The Peculiarities of Deep Sea Squid

The Peculiarities of Deep Sea Squid

(Passive Effect)
When any character with Invulnerability gains a turn, their Ultimate Skill cooldown is reduced by 1 turn, regardless of whether they are an ally or enemy.
Reduces all enemies' Effectiveness by 90% and increases the caster's Bleeding Damage Dealt by 100%.

At the end of the caster's turn, deals Fixed Damage equal to 10% of the target's Max Health to enemies without any buffs.
Increases damage taken from StrikerStriker enemies, and greatly reduces damage taken from attacks that target all enemies.
Cursed/Fixed Damage to the Boss cannot exceed 10000.

Deals significantly more damage when attacking fewer targets.

Enraged

Enraged

Becomes Enraged every 3 turns.

Enraged: Grants an irremovable effect to the caster that increases Attack and reduces damage taken for 3 turns. Restores 10% Weakness Gauge. Enraged lasts for 3 turns.

Thalassophobia: Used when Enraged ends.
Deals heavy damage to all enemies.


Tactical Tips

  • Any character with gains on their Ultimate.
  • At turn end, deals 10% Max HP to enemies without buffs.

Recommended Characters

Kanon
Fire
Striker
Poolside Trickster Regina
Water
Striker

Kanon, Poolside Trickster Regina

Essential pick for score bonus.

Caren
Water
Striker
Poolside Trickster Regina
Water
Striker

Caren, Poolside Trickster Regina

boss's .

Aer
Fire
Striker
Kappa
Earth
Defender
Eliza
Dark
Ranger
Regina
Light
Mage

Aer, Kappa, Eliza, Regina

boss's .

Delta
Earth
Striker
Fran
Earth
Ranger

Delta, Fran

buff (boss is fast).

Monad Eva
Light
Healer

Monad Eva

and support.


Suggested Teams

Recommended TeamRecommended Team

Remove from boss ASAP with or . Keep at least one buff on your team to prevent boss's .