Lost Sword Deep Sea Floor 100 Team and Boss Clear Strategy

To clear Deep Sea Floor 100 in Lost Sword, field a four-character roster featuring one durable frontline tank, one high-burst single-target damage dealer, and dual sustain supports. Turn the boss away from your backline to protect fragile allies from lethal frontal cleaves, use passive and active healing to outlast ambient ocean damage, and manually hold your major damage cooldowns until the boss’s break gauge hits zero.

Recommended Floor 100 Team Composition

Floor 100 enforces a strict enrage timer while dealing heavy area-of-effect damage, making single-healer setups vulnerable to sudden wipes. Run a dedicated frontline tank alongside dual healers or buffers to maintain full uptime for your primary damage carry.

Slot	Recommended Heroes	Role	Priority Stats
Frontline Tank	Crassa, Galahad	Taunt aggro, absorb frontal hits, provide barrier	Max HP, DEF, Damage Reduction
Primary DPS	Morgan le Fay, Aiden	Deplete break gauge, execute burst damage	ATK, Crit Rate (60%+), Crit DMG, Pierce
Main Healer	Elizabeth	Team-wide sustain, emergency burst healing	Skill Haste, Max HP, Healing Power
Utility Buffer	Lilia	Attack amplification, cleansing, secondary healing	Skill Haste, DEF, Effect Resistance

Crassa provides taunt uptime, defense amplification, and barriers to keep the boss anchored. If you run Galahad instead, use his invulnerability windows and barrier mitigation to absorb multi-hit skill sequences. Morgan le Fay serves as the primary offensive carry due to her high burst scaling and armor shredding during vulnerable windows.

Boss Mechanics and Threat Priorities

Navigating Floor 100 requires managing three distinct mechanics that will wipe underprepared teams:

Frontal Tidal Crash: The boss delivers a heavy physical cone attack. If your tank loses aggro or gets knocked backward, this strike turns toward your backline and can eliminate your supports instantly.
Ambient Ocean Pulses: The arena periodically pulses with unavoidable chip damage. Passive healing, defensive barriers, and sustained health recovery are required to prevent your supports from slowly falling into lethal range.
Stagger Break Gauge and Enrage: The boss features a stagger meter beneath its health bar. Depleting this meter incapacitates the boss and increases its damage vulnerability. Failing to deplete boss health before the stage timer expires triggers an enraged wipe state.

Step-by-Step Skill Timing and Combat Sequence

Do not leave skills on automatic cast. Floor 100 requires manual intervention to align your team's attack buffs and high-multiplier ultimates with boss vulnerability phases.

Phase 1: Opening Positioning (100% to 75% Boss HP)

Move your tank forward immediately at the start of the battle to face the boss away from your team. Cast your tank's taunt and barrier skills before the boss finishes its opening advance. Save Elizabeth’s burst heal until immediately after the first tidal crash lands.

Phase 2: Gauge Depletion (75% to 50% Boss HP)

Whittle down the stagger gauge using standard attacks and basic skills. Do not cast Morgan le Fay's ultimate while the boss retains active armor. Refresh Lilia’s attack buff when the stagger meter drops below 10%.

Phase 3: Stagger Burst Window

The moment the break gauge reaches zero, the boss is temporarily incapacitated and takes amplified damage. Instantly chain all stored offensive ultimates and high-multiplier abilities while Lilia's attack buff is active.

Phase 4: Sub-25% Enrage Burn

After recovering from stagger, the boss attacks with increased frequency. Reapply your tank's defensive barriers, trigger your pet's active skill, and cycle remaining burst skills directly into the boss to finish the encounter before the enrage timer expires.

Gear Stats and Pet Configuration

Hitting the survival and damage requirements for Floor 100 requires focused substats rather than relying purely on base gear tiers:

Primary Carry: Prioritize ATK, Critical Damage, and Pierce on gear substats. Aim for at least 60% Critical Rate so that burst skills land reliably during the stagger phase.
Frontline Tank: Focus entirely on Max HP, flat DEF, and Damage Reduction rolls, reinforced by Chaos Cube upgrades.
Supports: Equip accessories and armor rolling percentage Max HP and Skill Haste to ensure healing cooldowns rotate before ambient pulses wear down the party.
Pet Gems: Slot Pet Gems that boost party Max HP and damage reduction. If your team survives comfortably but fails the enrage timer, replace one defensive gem with an ATK gem to raise your overall damage output.

Troubleshooting Common Wipe Conditions

Party wipes in the first 30 seconds: Your tank failed to turn the boss, causing the opening tidal crash to hit your backline. Move the tank forward sooner and verify taunt timing.
Support dies midway through the fight: Ambient pulses are outpacing your recovery. Replace flat defense substats on your supports with percentage Max HP rolls and upgrade defensive Pet Gem tiers.
Boss wipes the team at low health via enrage: You lack sufficient burst during stagger windows. Do not run a third defensive support. Ensure Lilia’s attack buff is active before triggering Morgan le Fay’s ultimate, and verify your main carry meets the 60% Critical Rate target.