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Joint Challenge

Prototype EX-78 — Outerplane Joint Challenge Guide

By SevihUpdated 2025-10-28
Prototype EX-78 Joint Challenge Guide

Joint Challenge boss. The boss prioritizes the leftmost enemy, and if the target isn't a HealerHealer, it gains . Increased damage from EarthEarth and WaterWater enemies. Takes 100% increased WG damage from .

Prototype EX-78

Prototype EX-78

DarkDarkRangerRangerLv.120
Immunities
Guardian Slash

Guardian Slash

Attacks an enemy.
Prioritizes the enemy on the far left, and if the target is not a HealerHealer, grants the caster an irremovableReduced Damage effect for 1 turns.

Guardian Cutter

Guardian Cutter

Attacks all enemies, and grants increased Critical Hit Chance and Critical Damage to the caster for 3 turn(s).

Electric Cannon

Electric Cannon

Attacks all enemies. Grants Reduced Defense and Reduced Attack for 5 turns. (Ignores Immunity)
Right after using this skill, does not trigger an enemy's Counterattack, Revenge, or Agile Response.

Kill Mode

Kill Mode

(Passive Effect)
Increases damage received from WaterWater and EarthEarth enemies, and decreases damage received from FireFire, LightLight, and DarkDark enemies. When the caster is afflicted with Poisoned, damage received increases.
When attacked by an enemy with a debuff, the enemy's CP is reduced by 30.

Battle Command

Battle Command

(Passive Effect)
After attacking, if the caster has a removable Buff, recovers 10% of WG.
Takes 100% increased WG damage from Dual Attacks.
Damage from Fixed Damage cannot exceed 80000.
All attacks deal increased damage the fewer enemies there are.

Enraged

Enraged

Becomes Enraged every 4 turns.

Enraged: Grants an irremovable effect to the caster that increases Attack and reduces damage taken for 3 turns. Recovers 30% Weakness Gauge. Enraged lasts for 3 turns.

Stun Cannon: Used when Enraged ends.
Attacks all enemies. Has a 100% chance to inflict Stunned on the target for 2 turn(s), then permanently grants irremovable increased Critical Hit Chance to the caster.
The Stunned effect ignores the target's Resilience.


Tactical Tips

  • S1 prioritizes the leftmost enemy - place a HealerHealer to prevent buff.
  • Increased damage from EarthEarth and WaterWater, reduced from FireFire, LightLight, DarkDark.
  • Takes increased damage when afflicted with .
  • When attacked by debuffed enemy, reduces their CP by 30.
  • If boss has a dispellable buff, recovers 10% WG after attacking.
  • Takes 100% increased WG damage from .

Recommended Characters

Luna
Water
Defender
Viella
Earth
Healer

Luna, Viella

Essential pick for score bonus.

Monad Eva
Light
Healer
Veronica
Water
Defender

Monad Eva, Veronica

Alternative with .

Dianne
Light
Healer
Saeran
Earth
Healer

Dianne, Saeran

support if needed.

Ame
Earth
Mage
Rey
Earth
Striker
Noa
Earth
Striker
Ryu Lion
Earth
Ranger

Ame, Rey, Noa, Ryu Lion

EarthEarth DPS options.

Tamara
Water
Ranger
Charlotte
Earth
Ranger

Tamara, Charlotte

Support options.


Suggested Teams

Recommended TeamRecommended Team

Place a HealerHealer on the leftmost position to prevent the boss from gaining . EarthEarth and WaterWater DPS deal increased damage.