This is a featured article.

... Darkness coming.

—Aurora Unit 313

Aurora Unit 313 was the final boss in Metroid Prime 3: Corruption, and the final boss of the original Metroid Prime trilogy.


An organic supercomputer originally used to assist and interface with the crew of Federation starships, Aurora Unit 313 was stolen by Space Pirates from the G.F.S. Valhalla,[1] under the orders of Dark Samus. As it was being ripped from its chamber in the Valhalla, 313 left behind a final message to the Federation detailing its abduction. It was taken to Phaaze, where it was implanted into the planet and corrupted by Phazon. Seemingly as a result of Phaaze being a living organism, coupled with the Space Pirates' expertise in bio-technology, the organic supercomputer became symbiotically linked with the planet. Through the usage of AU 313 within the Sanctum, Dark Samus was able to control Phaaze, allowing her to systematically launch the Leviathans toward targeted planets at will.[2] Aurora Unit 313 also infected several of its fellow AUs located in Galactic Federation territory with a virus via their shared digital network, forcing the organization to shut down their systems and leave their territories vulnerable to an attack by the Pirates.

After Dark Samus is defeated by Samus Aran on Phaaze, the former merges with the Aurora Unit, forcing Samus to battle against it. To destroy it, Samus must first attack the open holes from which its tentacles emerge in order to stun it, then open the hatch on its head with the Grapple Lasso to reach its core and overload it with Phazon energy. Once this is done, the cable connecting it to the ground will break and reveal its weak point. It will fly around the arena during this part of the fight. At this point, Samus must attack the weak point where the cord once was.

Once Samus destroys it, Dark Samus is finally defeated. The destruction of the Aurora Unit begins a chain reaction, caused by the symbiosis of Phaaze and the AU, that ultimately culminates in Phaaze exploding.

313 also appears in a Diorama in the game's Extras menu. (See Gallery)

Battle attacks[]

Aurora unit body battle

The Unit's first form.

First form[]

  • A purple laser shot from the eye, which is easy to evade by jumping and side-stepping.
  • Sometimes the AU will retract into the ground and four cannons will shoot small energy balls.
  • The AU will often extend Phazon tendrils that will throw Phazon projectiles if they are not destroyed.
  • As a last resort the AU will call Dark Echoes to assist it.
Boss aurora8

The Aurora Unit in its second stage.

Second form[]

  • This is an attack from the Metroid Prime's core essence: the destructive energy wave. Shooting the node that drops the energy wave stops it and stuns the AU.
  • Another of its attacks consist of four lasers being unleashed from the four hatches on the sides of the AU. They arch and fall, leaving only the area directly below the machine safe.
  • The AU's central "eye" will glow blue and fire one or two blasts of Phazon. When the attack finishes the AU will be stunned. This attack is also used by Quadraxis when its head is separated from the body.
  • This attack consists of the AU spinning and flying around the room. An extremely accurate Screw Attack into the AU's weakspot will stop this.

Official data[]

Logbook entry[]

AU scan images
AU scan images

Aurora Unit 313

Metroid Prime 3: Corruption

Temporary scan

Morphology: Aurora Unit 313
Hatch on its head protects core. Damage core to sever cables.

Morphology: Aurora Unit 313
Severed cable has exposed a weak point that is vulnerable to attack.*

Logbook entry

Aurora Unit 313 has somehow been fused with the bioessence of Dark Samus. While combat shields protect most of the unit, a weak spot has been detected at the cable junction. Damaging the unit's core will expose this point, but the core itself is protected by an armored hatch. Tentacle ports can be damaged to initiate stunning cerebral-feedback pulses within the target. While incapacitated, the hatch will be unprotected and able to be pulled open. This unit has been heavily mutated by Phazon exposure. It appears to be symbiotically connected to the planet Phaaze as well.

* When cable has been severed.


"Aurora Unit 313 has been temporarily stunned. Hatch on its head can be pulled open."

Unused Logbook entry[]

"What's the matter? All I said was that Komaytos look like little Metr-"

Non-canon warning: This article or section contains information that may not be considered an official part of the Metroid series in the overall storyline by Nintendo.

Aurora Unit 313

Metroid Prime 3: Corruption

Temporary scan

Galactic Federation Datafile AU-313.
(Aurora Unit 313)
Data moved to Logbook for review.

Logbook entry

Before its abduction from the G.F.S Valhalla, Aurora Unit 313 was in service for twelve years. Available data indicates that the unit is out of order, and was possibly involved in the corruption of the Aurora network. 313 has always shown a satisfactory performance during its career, however, there were concerns about its unusually high aggression potential. As one of the few AUs, 313 was awarded the medal of honor. After the bridge crew fell during the Battle of Horus IV, it assumed command of the Valhalla. Without this fast action, the battleship would have been lost.


Non-canon warning: Non-canonical information ends here.

Valhalla message[]

AU 313 model

In-game model for the first form of AU 313.

On the G.F.S. Valhalla, there is a Key Code terminal in the Control Room of the flagship that displays a message from the invasion of the Valhalla. This message can only be seen by entering the Access Code "78356". This code can be seen on a PDA device belonging to a deceased Federation Marine in the same room. The Aurora Unit 313 describes how the Federation were unable to repel the attacks of the Space Pirates upon the ship, and how 313 was forcefully taken from the Valhalla. Near the end of the transmission, 313's voice fades, as it is somehow shut down. With its last words it reveals the Pirate's intentions for stealing the Aurora Unit:

"Data log entry 2467.3. This will be the last communication of the G.F.S. Valhalla. Our efforts to repel the Space Pirate boarding force have failed. They have successfully removed the primary mounting structure around our stasis tank. It is obvious now that they intend to extract us from the Valhalla. It is vital that the Federation receive this transmission.
...Severing main power...
A large bioform is creating a wormhole...
...Implant into...
Sentient planet which is the source of all Phazon.
...Darkness coming."



Au 313 drone damaged

Samus damages 313's extended drone.

  • During the first phase of the battle with 313, the AU will sometimes extend what appears to be an optical drone from one of the ports on its head. Firing upon this drone will cause 313 to enter a stunned state in which several of its ports will be susceptible to attack.
  • After the network in SkyTown is restored, the corrupted AU 313 is displayed on the many breakable monitors all over the place instead of 217. Despite this, the scan states that it is displaying 217.
  • Unused GF records refer to 313 as female. Gendered pronouns are never used in reference to 313. It is possible that 313 has a gender-neutral configuration, which some AUs are said to have.
    • Unused scans for Aurora Unit 313 mentioned that it had an abnormally high aggression potential even before Dark Samus and the Space Pirates stole it.
    • The voice for 313 in its last transmission depicts it with a very deep voice. During the final battle, however, thanks largely to Dark Samus possessing it, it utilized Dark Samus's voice clips.
  • 313 shares many similarities with Mother Brain. This is seen in the purple energy laser that resembles Mother Brain's eye beam in Metroid: Zero Mission or the Hyper Beam in Super Metroid, the red spheres of energy that resemble the Rinka defense system and Cannons. 313's eye is also larger than the eyes of the other Aurora Units and bears more resemblance to Mother Brain's eye. Also, when the hatch in the Aurora Unit is opened, a brain-like organ is shown within.
  • The theme of 313 is a remix of Darkness, arranged in a way that resembles Zebetite, Mother Brain's theme from Metroid: Zero Mission. The "cable" that connects 313 to the floor in its first phase resembles the neck of Mother Brain's body from Super Metroid. 313's death is also similar to Mother Brain's death in Super Metroid: both shrivel and die, and their death results in the explosion of a planet. The cable also seems to invoke the anatomical imagery of a spinal cord attached to a Brain, which seems very similar to Mother Brain's show appearance on Captain N: The Game Master.
  • Considering superstition; 313's last two numbers are 13, the number that is infamously associated with misfortune and bad luck. This would seem to be the case as the Space Pirates attacked the Valhalla that 313 was stationed on, and became the one unfortunate Aurora Unit chosen to be linked to and then corrupted by Phaaze.
  • Ian Olsen modeled and skinned 313.
  • At times, AU-313 lets out a laugh during its first phase of its respective boss fight after it gets temporarily dazed.