Quadraxis was a colossal security drone created by the Luminoth to protect the Sanctuary Fortress. However, the Ing conquered the fortress, and a large number of the dark creatures possessed Quadraxis, taking the immense drone to guard the Ing Hive instead. The security drone is battled as the third Guardian of Dark Aether's planetary energy by Samus Aran. Once defeated, Quadraxis' head module crashes into the ground and rewards the Annihilator Beam. The body of Quadraxis dissipates into Ing matter after it is collected.


First Phase[]

Quadraxis, in its first form, uses single shot and charged matter-antimatter blasts (the annihilator beam), missiles, machine guns, and a vortex spin akin to that used by Quads. The only difference is that while the Quads spin around the arena trying to ram Samus, Quadraxis will stay in the middle of the arena, attempting to suck her into it. One way to avoid the vortex spin is to get on the far edges of the arena when it begins to start this attack; another is to shoot its feet with a charged beam or Screw Attack into it.

Quadraxis is damaged by shooting its four knee joints. Its foot weaponry may additionally be disabled with the Boost Ball or Morph Ball Bombs to yield pickups, but this will not inflict damage, and all feet will regenerate after each knee is destroyed.

Second Phase[]

Quadraxis' Head escapes the Body.

Once Quadraxis' legs are crippled and unable to function, it will collapse in a broken heap - unfortunately, its head will detach from the body and fight on its own. The head will use a shielding device which receives tactical data from the body; using the Echo Visor, Samus must destroy the transmitter on the body and attack the 3 receivers on the head. Once one receiver is destroyed, Quadraxis will try to re-establish the lost link, summoning Dark Quad robots in the process. Samus should either ignore the robots or destroy their heads and keep moving so the bodies cannot spin into her. If she takes the time to completely destroy the Quads, Quadraxis will probably re-establish the link to its body and resume its attack.

Final Phase[]

Samus lays a Morph Ball Bomb in one of the ports in the Head during the final phase.

Once all the receivers are destroyed, Quadraxis will fly around erratically, crashing into its body's legs and dislodging their armor, revealing Spider Ball Tracks. It will eventually regain control and continue battling Samus, but the bounty hunter's previous assault has disabled its shields and most of its weaponry.

To finish the rogue mechanoid, Samus must attack the head unit until it is stunned, at which point it will slowly circle its ruined body. Using the damaged legs as ramps, Samus must time a jump with her Boost Ball to propel herself onto the floating head with the Spider Ball allowing her to cling to its surface. From here, she can move into one of the two Bomb Slots on Quadraxis' head and lay a bomb to injure the robotic Guardian. Once bombs are dropped in both slots, Quadraxis' head will fall to the ground and explode, leaving behind the Annihilator Beam. Once the Annihilator Beam is acquired, a large platform will rise in the center of the room with Spider Ball Tracks on the side of it, allowing Samus to finally escape the temple.

Logbook entries[]

Disassembled parts
"Object scan complete. This is a component of an incomplete mechanoid. Design similarities exist between incomplete unit and the rogue mechanoids of Luminoth design found throughout this area."


Temporary scan

Mechanism: Quadraxis
Rogue high-security drone.
Heavily armed and armored mechanoid. Lightly armored foot joints are vulnerable to Bomb and Boost attacks.

Logbook entry

The Quadraxis unit went rogue and entered the service of the Ing. Its primary weapon system fires destructive matter-antimatter blasts. It uses a powerful missile battery for long-distance attacks. The Quadraxis is incredibly durable and well-armored, but its leg and foot joints are vulnerable. Damaging these joints will eventually render it immobile.

Damaged Quadraxis

Temporary scan

Mechanism: Damaged Quadraxis
Dedicated sentry building unit.
Main body rendered immobile. Sonic tactical data bursts detected. Destroy transmitter to disrupt operations.

Logbook entry

Though the main body is disabled, the tactical control unit within it is still active. It will guide the Head Module in battle via high-sonic transmissions. Disabling this module will impair the Head Module's ability to fight.

Shielded Head Module

Temporary scan

Mechanism: Shielded Head Module
Command Module of the Guardian unit.
Highly mobile and well-armed. Impervious force shield protects it from harm. Receiving tactical data via high-sonic transmissions.

Logbook entry

The Head Module of Quadraxis is highly mobile and well armed. It is shielded by an impervious force field. Tactical commands are sent to the module from the crippled main body: sever this link to impair the Head Module’s combat ability.

Stunned Head Module

Temporary scan

Mechanism: Stunned Head Module
Battle logic disrupted. Unit is vulnerable.
Shield offline. Unit is generating drones for defense while trying to restore sonic tactical link with main body.

Logbook entry

Mechanism: Shielded Head Module
Command Module of the Guardian unit.
Highly mobile and well-armed. Impervious force shield protects it from harm. Receiving tactical data via high-sonic transmissions.
Head Module is unable to receive tactical data. Force field offline. Unit is generating drones to defend itself while it attempts to restore tactical link to main body. Destroy sonic receptors on unit to prevent this.

Final Head Module

Temporary scan

Mechanism: Final Head Module
Tactical ability reduced. Unit now vulnerable.
Link to main body severed. Two weak points detected; target them with concussive blasts to damage the unit.

Logbook entry

Module has lost its tactical link to the main body. Two points of structural weaknesses have been located on its hull: Morph Ball Bombs can cause damage to these areas. Scans indicate that the Spider Ball can attach to the Module's outer hull.

Development notes[]

Promotional art of Samus fighting Quadraxis.

In unused data from the Metroid Prime 2: Echoes Bonus Disc, Quadraxis was named the "Steadfast" class Guardian. In addition, the Shielded Head Module was named the Steadfast Head Module, and contained Splitter Microfactories that generated Splitter class sentry drones (known as Quads in the final game). These names were likely changed in development.

Quadraxis was designed by Mike Wikan, and was one of his favorite bosses from the Metroid Prime series.[1] Wikan felt that the Quadraxis fight worked because of the camera system designed by Mark Haigh-Hutchinson.[2]

Kynan Pearson said in an interview with Shinesparkers that the name "Quadraxis" is a portmanteau of "quadruped" and "axis". [3]

Vince Joly animated all of Quadraxis' cutscenes.


  • Quadraxis' head possesses three "eyes" connected to form a triangle. This symbol, resembling the Luminoth letter "F", is found on many other artifacts of that species, and on the Luminoth themselves.
  • Disassembled parts of Quadraxis can be seen scattered throughout the Fortress Temple entrance, suggesting that the Luminoth were in the process of making more than one.
    • This could also suggest that the parts were already on Dark Aether when it formed, and the Ing somehow managed to properly assemble it; the parts lying about on Light Aether could suggest that the Luminoth did not manage to finish Quadraxis before their defeat, or that they did not want another Quadraxis to be possessed by the Ing.
  • Due to the similarities between Quadraxis and the Quad robots, it can be considered a larger, more powerful version of them; essentially an Alpha Quad despite not having the word Alpha in its name.
  • Quadraxis is one of the largest bosses in the Metroid series, alongside Kraid, Mogenar and Phantoon.
  • Quadraxis' head, when exposed, shares a few similarities to an Aurora Unit.
  • In early screenshots, Quadraxis was blue with green armor. Another notable fact is that even though it briefly changes color when possessed at the beginning of the battle, it is the only possessed creature in the entire game to maintain its original color scheme.

Concept art from Corruption.

  • Probably because of the Ing controlling it, Quadraxis is most vulnerable to the Light Beam.
  • The music heard when battling Quadraxis is a remix of the Ing Battle theme.
  • Samus can reach Quadraxis without the Ing Hive Keys, by Sequence Breaking.
  • In the cutscene for Quadraxis' defeat, Samus disengages from the Final Head Module and uses the Gravity Boost to slow her descent. This is interesting because the Gravity Boost cannot be used in this manner during gameplay.
  • Unlockable artwork for SkyTown in Metroid Prime 3: Corruption shows a strange structure, with a Quadraxis-style head atop it.
  • Quadraxis' battle formula is similar and comparable to that of Stallord, a boss from The Legend of Zelda: Twilight Princess. The idea is that the first phase deals with the whole entity itself by damaging the body, and then the second phase has you going after its floating head. However, Stallord isn't a machine, but a giant fossil powered and animated by Zant's black magic.
  • The battle also resembles Fionn mac Cumhaill's battle against Cat Head, in the Celtic legends regarding said hero. Cat Head was sent forth by his mother, an evil witch, to discover what had become of his brothers; upon discovering his brothers had been killed by Fionn Cat Head fought Fionn, but Fionn fought and killed Cat Head. However, Cat Head's head rose from his body and continued to fight, biting Fionn brutally, and was only killed by Fionn killing the witch and throwing her blood at Cat Head, who died.
  • In the recent blockbuster "Prometheus" by Ridley Scott, the spaceship Prometheus strongly resembles Quadraxis, particularly the knee joints.[citation needed]
  • Quadraxis may be heard speaking in the Luminoth language in a deep, robotic voice. This can easily be heard during the second phase of the boss fight, right after it separates its head from its body.
  • Surprisingly the Annihilator Beam can affect Quadraxis (if hacked in during the fight). However; Quadraxis's antennae from the legs do not receive damage from normal shots, the stunned head antennae are completely unaffected by any Annihilator Beam shots, and the final Head Module only receives stun damage from Charged Annihilator Beam.
  • A glitch can occur when using the Screw Attack just before triggering the cutscene for the second phase of the battle. When the cutscene ends and Samus regains control, the HUD will display will be glitched, displaying incorrect information such as displaying Power Bomb information and both Quadraxis's and Samus's Health meters not being accurately aligned.
  • Firing at Quadraxis's un-stunned Final Head Module using Phazon bullets (via hacking) will cause any shots to pass right through the module.



  1. ^ Vikon99. "I was the Game Designer who designed this Boss (among others). Well done! Quadraxis is one of my favorites from the entire Prime series and it's great to see him here. -Mike" February 21, 2020. Thingiverse. Retrieved January 3, 2021.
  2. ^ KIWI TALKZ - #105 - Mike Wikan Interview (Metroid Prime Trilogy, Game Design, Crunch, Booz Allen Hamilton etc.) September 6, 2021. Retrieved March 16, 2022. (24:09)
  3. ^