The Ether Superboss in Astral Chain stands as the most formidable opponent in the game—a true test of everything you’ve learned throughout your journey. With extreme aggression, unpredictable phase transitions, and punishing attacks, Ether demands both skill and preparation. This guide walks you through a reliable strategy for defeating the super boss, from Legion setup to in-fight execution.

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Overview: The Setup and Why It Matters

To even face Ether, you must first complete all other combat cases, meaning you’ll likely be well-equipped by the time you reach this challenge. But preparation doesn’t stop at gear—it hinges on smart Legion configuration, cooldown efficiency, and buff synergy.

While you can beat Ether with a minimal loadout, this guide is about optimizing your success and aiming for S+ ranks.

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Legion Configuration: Skills & Strategy Per Type

You’ll use all five Legions, but the core of your strategy focuses on three: Beast, Axe, and Arrow.

Shared Core Skills (Arrow, Sword, Arm):

• Power Charge – Key to burst damage. Buff before every offensive combo.
• Hit Rush – Summons your Legion for autonomous attacks. Used for crowding Ether, staggering, and distracting.

You’ll be rotating between Legions to keep a near-constant uptime on these buffs. Quick cooldowns are critical—apply them liberally across all relevant Legions.

Axe Legion:

• Blue Shield – Offers a window of invulnerability for risky trades or survival during Ether’s deadliest sequences.
• Auto-Bind – Doesn’t stun Ether outright but contributes to stun buildup when paired with follow-up attacks.
• Slow Attack+ – Slows Ether, increasing combo safety and control.
• Super Armor Omega – Optional but useful for trading hits without interruption.

Beast Legion:

• Speed Star – Buff for repositioning, evasion, and setting up final phase rushdown.
• Howl – Arguably the second-best skill in the game. It’s unaffected by diminishing returns and is essential for triggering stuns.
• Slow Attack+ – Pairs with Hit Rush and mount dodging for easy proc chance.

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Passive Abilities and Legatus Optimization

Aside from active skills, equip:

• Cooldown Reduction (on all Legions)
• Slow Attack+10% (especially on Axe and Beast)
• Super Armor Omega (for clutch Beast survivability)

Max out your EX-Baton and Legatus. The Legatus difference alone is massive—higher ranks mean faster energy recharge and nearly constant Legion availability. If your energy dries up, you’re as good as dead.

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Pre-Fight Loadout

• Items: Spicy Cobras, Reso Max, healing grenades
• Start with Reso Max to pre-fill your gauge before the first phase
• Have Beast Legion as your quick-switch default

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Phase 1: Tempo and Stagger Control

Start with Arrow + Hit Rush, then quickly switch to Beast to trigger a Slow, followed by Howl for stun. This is the basic cycle:

1. Stun Ether → activate Power Charge, Spicy Cobra, and Speed Star
2. Switch to next Legion → Hit Rush
3. Return to Axe or Beast to apply follow-up pressure
4. Chain attacks to keep Ether in stun/slow rotation

This phase is forgiving. Aim to bring Ether’s HP down to just below 50% while conserving cooldowns and energy.

Key mechanics:

• Vortex spin: Easy dodge—use it to reposition.
• Fireballs: Mount Beast to avoid and attack from the rear.

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Phase 2: The Flurry Phase (The Real Fight Begins)

Ether amps up with rapid flurry attacks and elemental barrages. This phase is deadly:

• Stay mounted on Beast as often as possible.
• Use Howl to interrupt Ether’s attack chains.
• Auto-Bind + Hit Rush helps manage positioning.

Key attacks to watch for:

• Flurry Slash Combo: Avoid at all costs. If you see it incoming, mount Beast or activate Blue Shield.
• Clone Phase: Use grenades or AoE to clear out clones.
• Black Hole: Target Ether immediately to prevent a loss of control.

Maintain slow uptime. The moment you get a Slow proc, throw out a Howl, then chain all buffs into your offensive loop. Time is your ally—play slow and safe.

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Final Phase: Legion Fusion Finisher

When Ether hits ~10% HP, prepare your finisher sequence:

1. Apply Power Charge, Speed Star, Spicy Cobra.
2. Activate Legion Fusion (use your highest-damage Legion, ideally Axe).
3. Unleash.

Important: Don’t trigger Fusion until you’re sure you can finish the fight. Fusion leaves you vulnerable afterward, and Ether will punish that with a one-shot.

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Closing Tips

• Don’t rush—especially in phase two. Rely on slows, stuns, and positioning.
• Use the environment to bait Ether into open spaces.
• Blue Shield and Hit Rush are essential to absorbing pressure and keeping up DPS.

You don’t need perfect execution to S-rank the fight. What you need is familiarity—know the patterns, when to engage, and when to hold back.

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Final Thoughts: Ether Is the Endgame Test

Defeating Ether is the culmination of all your learning in Astral Chain. While the fight offers no glamorous reward (beyond the Lucky Onus license and empty cans), its value lies in mastery. It’s you vs. the limits of the combat system.

Everything—from chain mechanics to dodge flow, Sync timing, and Legion micro—gets pushed to the limit. So if you’ve come this far, you already have the tools. With this guide, now you’ve got the plan.