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For the Butterfly Effect's main series counterpart, see Mytyl.


"P L E A S E... K I L L M E."
Butterfly Effect , Luminous Avenger iX

The Eternal Peacekeeping Device, Butterfly Effect (恒久平和維持装置バタフライエフェクト) is a device used by the Sumeragi Institute of Human Evolution to locate and control Adepts. Copen spends much of his time searching for it during the events of Gunvolt Chronicles: Luminous Avenger iX.

Once having been Copen's younger sister, Mytyl, she was captured by Sumeragi under Demerzel's command, implanted with her septimosome recovered from the corpse of Joule, and used as a replacement for the "Queen piece" in his plan. It wields The Muse Septima, which gives it the ability to locate and enhance other Septima. It is the power source of the Falcon Quills, and acts upon the subconscious of Adepts across the world to slowly reduce their interest or concern for Minos[1].


The Butterfly Effect takes the horrific form of a human brain, greatly enlarged as a side effect of repeated life extension procedures[1] and hooked up to a machine. This machine holds it in place, and uses an apparatus to harness its power and project it using what appear to be red speakers with white trims. There are countless wires stemming from the machine, all varying in length and width, and most of them being blue and red.

Plot Role

As per Demerzel's wishes, The Butterfly Effect serves as the cornerstone for supporting his elite Adept soldiers. While we assume the Butterfly Effect has been active for a long time, it's ambiguous exactly how long Demerzel has been using it.

Upon encountering it, Lola comments that even without a body, she can feel that Mytyl is crying. Mytyl begs for Copen to put her out of her misery, with a glitched message on the nearby screens reading "please, kill me" ("Acura-kun. Please... Kill me" in the Japanese version of the game). After Copen defeats it, it types out its final message, "thank you," before being sent to eternal rest.


Skill Description


At the start of the fight, the Butterfly Effect generates a large barrier that blocks all attacks and tagging attempts. It can be destroyed, but will regenerate after 10 seconds.

Butterfly's Flight

The Butterfly Effect spawns 2-4 clones of Lumen that fly at varying elevations. Stellar Spark will destroy them.

Butterfly's Lament

The Butterfly Effect spawns a dark clone of Lumen on either end of the screen, which flies forwards as it rains lasers and explosions along the ground.

When tagged on either the machine or the barrier, the flashfield generated by Stellar Spark (tagged version) will destroy it and interrupt the laser shot early should it be spawned at the machine's side.

Butterfly's Scream

Two dark Lumens are spawned on the top and bottom rows of the arena to fire lasers that only leave safe zones in the upper corner or in between. A third Lumen is then summoned to fire a gigantic laser in the middle safe zone.

When tagged on either the machine or the barrier, the flashfield generated by Stellar Spark (tagged version) will destroy them and interrupt the laser shots early.


Should it reach its final health bar and not be killed in time, Butterfly Effect instantly heals for up to two health bars. Repeatedly using Orbital Edge on the cords connecting the machine to the brain will cut them, preventing Anthem from being used.


  • The term "Butterfly Effect" is from the chaos theory principle of the same name, in which a small action in a series of events can drastically change the outcome. This references how Luminous Avenger iX is a split timeline from the original Azure Striker Gunvolt, derived from the bad ending rather than the true one.
  • Incorporated into a few sections of Butterfly Effect's boss music is Mytyl's theme from Azure Striker Gunvolt 2.
  • The machine above the brain resembles the capsule that Joule was restrained in during Azure Striker Gunvolt.
  • In the good ending of Azure Striker Gunvolt, Joule's body vanished in a beam of light after her Septima and soul merged with Gunvolt. It is unknown exactly why her body remained behind instead in the Luminous Avenger iX timeline, but may be due to Gunvolt's death denying her a new host.
    • An alternate theory is that, as a "Living Glaive", Joule's body simply teleported away like the Glaives of the bosses in ASG1 when they were initially defeated.
  • The EX Boss version of Butterfly Effect is one of the two bosses that can only be accessed through VS missions, the other being Giga Lola.
    • The only visible difference of EX Butterfly Effect is EX version has more health.
  • The Butterfly Effect does not appear to possess a main illustration, as in the Luminous Avenger iX Soundtrack it is only represented by its game sprite. It shares this trait with the intro stage medium boss Mantis Zombie.
  • Possibly due to it's overall designation, Butterfly Effect has the weakest stamina among the bosses.
    • Although this is largely compensated by its barrier and emergency healing ability.