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Mother Brain

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Mother Brain (マザーブレイン, Mazā Burein) is a recurring antagonist and boss in the Metroid series, and is also considered the main antagonist due to her being the main villain in four installments and the prequel. She is a cold artificial intelligence created by the Chozo, but turned against them when the Space Pirates and Ridley invaded Zebes. Mother Brain saw potential in the pirates and decided that with their help, she could bring true order to the universe by "resetting everything back to zero".

Mother Brain was seen as a main antagonist in Metroid, Super Metroid, and Metroid: Zero Mission. She is also seen in a flashback during and in the form of MB, the of main antagonist Metroid: Other M. In the Japanese website for Zero Mission, she is given the title Mad Overseer. Additionally, in the cartoon series Captain N: The Game Master, Mother Brain appeared as the main villain.


Mother Brain resembles a human brain, though she is more spherical in shape. She has short metal spikes protruding from the top of her "head" and a single gigantic eyeball with a red iris. Unlike the Federation's Aurora Units, which are neuron masses enclosed in metallic shells, Mother Brain's hide is strong enough that she remains completely exposed. Several power cables come off the bottom of her body, and she appears to be permanently attached to the floor of her tank, unlike the Federations' Aurora Units, which are free-floating. Her tank, called the Control Capsule in the Super Metroid comic, is made of Zebetite and is protected by multiple gun turrets, Rinka, and more Zebetite barriers which serve as both protection and energy resources.

In Super Metroid, she has a number of changes. She is now an orange color and appears to be more mechanized. Her eye is now white and has no pupil (though Metroid: Other M appears to have retconned this and gave her a more detailed eyeball) and she has a metallic mouth, complete with tongue and spittle, from which she can roar. Her most notable addition, of course, is a new mechanized body, which connects to her immediately following forcible disconnection from her capsule's life-support systems. The body itself stands taller than Ridley and is capable of dozens of attacks, including red energy beams, bombs, blue ring lasers, beam shots via her eye, and her most powerful attack, the Laser Brain Attack. This mechanized body strongly resembles a Torizo, suggesting similar technology.

Metroid Manga

Mother Brain's flying monitor system. Mother Brain can monitor Zebes with its camera eye and communicate through it.In the Metroid Manga, Mother Brain begins as an ally of the Chozo. The Chozo use her to keep track of data and reports.

When Samus disarms a number of Iona Faria that had been "corrupted" but doesn't kill them, Mother Brain orders sentry robots to kill them instead, angering Samus. The manga shows Mother Brain's frustration with the Chozo and with the many raids of the Space Pirates. She also mentions the Metroids as being her and the Chozo's children.

Later on, she takes it upon herself to "dispose" of many of the Chozo, calculating that by taking command of the Space Pirates, she could bring true order to the galaxy. She designated herself, a Chozo named Grey Voice, Ridley, and Samus Aran as Space Pirate commanders, though Samus refused to cooperate.

Mother Brain also stated that she was the one who created Samus's Power Suit.

After it is revealed that Grey Voice has only been pretending to be a Space Pirate commander so that he can get closer to her, he attacks Mother Brain, claiming that even though he will allow the Pirates to have the planet, he will not allow a "defective" product to continue. However, Grey Voice soon discovers that the Zebetite shield is too strong and that his attacks cannot get through; Mother Brain is then rescued by Ridley, who comes and battles with Grey Voice.

Later on, it comes to light that Mother Brain is in fact using the Pirates to further her own goals, and that she is using them to fight the Galactic Federation so that both become weakened. She plans on using an "evolved" form of the Metroid, an intelligent one, so that she may become the ruler of the universe. She seems to refer to all beings, from the Pirates to Ridley to the Federation, as simple beasts.

In the games


Mother Brain (Metroid NES)

Mother Brain (Metroid NES).

Mother Brain as she appears in Metroid. In Metroid, Mother Brain is the final boss in the last room of Tourian. She appears as a large brain within a glass stasis tank protected by Zebetite, Rinka, and turrets. The brain itself does not attack in any way after the tank is broken, unlike in the remake Metroid: Zero Mission. The Mother Brain also constantly regenerates life, much like the Zebetites, and the only way to tell how much damage she has taken is by how quickly she pulsates. If left alone, the pulsating will slow, and Mother Brain will heal herself. After Mother Brain has been destroyed, a self-destruct sequence begins, and Samus is forced to evacuate Zebes immediately. The manual for Metroid states that Mother Brain is the leader of the Space Pirates, which would mean Ridley is under her command, but not necessarily under total control.

Metroid: Zero Mission

Mother Brain (Metroid Zero Mission)

Mother Brain (Metroid: Zero Mission).

In Metroid: Zero Mission, Samus's main objectives are to destroy all Metroid organisms on Zebes and defeat the biological super-computer, Mother Brain, as in the original Metroid. The re-rendered version of Mother Brain shares a slight resemblance to Super Metroid's take. She is located in the lowest area of Tourian and is protected by the classic Zebetites, Rinkas and turrets. There have been some changes not only to Mother Brain's appearance but to her attacks and weaknesses as well. When her stasis tank is damaged and destroyed by Samus with several missiles (in the original NES game, it took but 1 missile to destroy it), Mother Brain starts countering by gathering energy into her brain and releasing it as a blast from her eye; this eye beam could be considered as a precursor/basis to the Hyper Beam the Mother Brain would have in her resurrected Super Metroid form. Unlike the NES Metroid and Super Metroid appearances, Samus can only wound the boss by firing directly at her eyeball.

Every time Samus hits the weak spot with either 5 missiles (3 on Hard difficulty), 1 Super Missile, or drops into the lava in the room, Mother Brain closes her eye and resumes the beam attack as soon as Samus gets back up. Surprisingly, Mother Brain does not appear as the final boss of the game. After Mother Brain is defeated, Samus evacuates Tourian, takes flight and is ambushed by Space Pirates. After crash-landing on Zebes, Samus ends up having to board the Space Pirate Mother Ship in her Zero Suit with only an emergency pistol to defend herself.

Unlike in Super Metroid, Mother Brain does not use a mechanical body and remains stationary. A revisit to Tourian after acquiring the Fully Powered Suit reveals a hidden chamber underneath Mother Brain's capsule that was also present in Super Metroid. This may indicate that her body was planned but not fully implemented, or could have simply been a cache of life support systems connected underneath Mother Brain. The pools of lava have also been replaced by an extremely corrosive green chemical, the only substance in Zero Mission capable of harming Samus even while she is wearing the Gravity Suit.

Metroid Prime 3: Corruption

The future Aurora Unit complex.In Metroid Prime 3: Corruption, it is revealed that the Galactic Federation uses organic super computers known as Aurora Units, brain-like neuron masses in tanks that closely resemble Mother Brain. The Mother Brain was built by the Chozo, though the manga indicates that the Federation had some part in this as well as she was built to link the Federation and Chozo information databases, similar to the function of the Auroras. Also, the Metroid Prime 3: Corruption trailer for Aurora Units shows a "future Aurora complex" which bears a near-identical resemblance to the Mother Brain's room in Super Metroid.

Also, the final boss of the game, Aurora Unit 313, features many references to Mother Brain, such as its cannons firing red spheres that look similar to Rinka, the purple laser that bears resemblance to Mother Brain's beam attacks, and the cable that supports 313 that is similar to Mother Brain's neck in Super Metroid. The Aurora Unit 313 theme is an arrangement of Darkness, Dark Samus' theme, arranged in a way that resembles Mother Brain's theme in Zero Mission.

This along with the Federation's seemingly corrupt actions at the end of Metroid Fusion might indicate a deeper and darker meaning with the Aurora Units.

Super Metroid

Mother Brain (Super Metroid)

Mother Brain (Super Metroid).

Mother Brain's first form in Super Metroid. In Super Metroid, Mother Brain is the final boss, living in the last room of Tourian. The battle against her remains the same initially. Once Samus defeats her, the actual brain itself falls to the ground and turns pale. After a short wait, she starts to rise up and is seen to be connected to a mechanical body, possibly built by the Space Pirates, indicating that she had learned from her mistakes in her last encounter with Samus.

Super Mother Brain (Super Metroid)

Mother Brain's alternate form (Super Metroid).

Mother Brain uses a new weapon known as the Laser Brain Attack against Samus, which not only depletes an enormous amount of Energy Tanks, but also depletes Samus' Missile, Super Missile and Power Bomb ammo. When Mother Brain is about to finish her off, the Baby that she found on SR388 latches itself onto Mother Brain, absorbs her energy, apparently killing her, and returns it to Samus. An injured Mother Brain slowly reactivates and stands back up, and angrily attacks the Metroid as it covers Samus. As the Metroid lets go of her and lunges at Mother Brain once more, she delivers a killing blow, and the remains of the Baby fall over Samus.

At that moment, Samus realizes that the Metroid was able to grant her the power of the Hyper Beam, which it stole from the Mother Brain. Enraged, Samus opens fire and defeats Mother Brain with her own beam attack. Afterwards, Mother Brain's body is destroyed, causing her head to fall down and become pale. Mother Brain's head then weakly opens its mouth and finally turns to dust. Once Mother Brain dies, a Countdown starts, destined this time to end in the obliteration of the entire planet. Samus evacuates Zebes once again before it explodes with her on it. As of Super Metroid, Mother Brain has been eradicated from the universe, and resurrection is unlikely.

Metroid: Other M

Mother Brain makes an appearance in Metroid: Other M, just before slaying the baby Metroid. A 3D version of Super Metroid's Mother Brain battle is featured in the Metroid: Other M intro cutscene, recreating the climax of Super Metroid. The Infant Metroid carries Samus (as if it were holding a corpse, though the hatchling is recharging her energy) in the air before being destroyed by the Hyper Beam. It then explodes over Samus into many small particles, resembling a rain of snow. Mother Brain then moves to destroy Samus, who whispers "Mother! Time to go..." and finishing her off with the Hyper Beam.

Melissa Bergman

Melissa Bergman aka MB ("Mother Brain").

Although she herself doesn't reappear, her consciousness and data was used by the Galactic Federation to create an AI known as MB for the purpose of helping breed Metroids, and in a sense became Mother Brain's reincarnation.There is also some hints that Phantoon is the manifestation of Mother Brain's consciousness.

Leadership Debate

Mother Brain's role in the Metroid series is vague. There is a debate as to whether she or Ridley is the leader of the Space Pirates (this question growing more confused with the addition of High Command from the Metroid Prime games). Her body appears to be based off of Torizo technology.According to Super Metroid's manual, Metroid: Zero Mission's manual, and the official manga, Ridley is the general of the Space Pirates while Mother Brain is the biological computer which controls Zebes' defenses.

However, Metroid's manual, Metroid Fusion's manual, Metroid: Zero Mission's game box, the Super Metroid Nintendo Power comic, and Super Metroid's in-game introduction refer to Mother Brain as the leader of the Space Pirates, with Metroid's manual saying that Ridley is controlled by Mother Brain. The manga later retcons this to rectify any confusion by stating that Mother Brain took over as one of the pirates' leaders, while keeping Ridley in his former position. Also, her referring to Ridley and the other Space Pirates as "simple beasts" might help explain the previous statement of Mother Brain controlling Ridley.

The Space Pirate Data in Metroid Prime refers to a High Command that commands the Space Pirates, which included ordering Ridley to be reconstructed. Whether or not Ridley is part of High Command is unclear. He may be the Pirate general, answering to High Command and/or Mother Brain.

Super Smash Bros.

Mother Brain appears as an Assist Trophy in the video game; Super Smash Bros 4 for the Wii U and 3DS. When Mother Brain is summoned, energy rings attack the opponent. While that's going on, Mother Brain grows in size. She then processes to shoot a powerful beam out of her eye.


  • listed Mother Brain as #5 on their Top 10 "Female Video Game Villains" list.
  • In Captain N: The Game Master, Mother Brain is voiced by the late Levi Stubbs (ironically a man), who also voiced Audrey II in Little Shop of Horrors.


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