Fantendo - Game Ideas & More
Fantendo - Game Ideas & More


Mother Brain (マザーブレイン, Mazā Burein) is the main antagonist and a recurring boss in the Metroid series. She is a cold and ill-tempered AI 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 them helping, she could bring true order to the universe by "resetting everything back to zero". Mother Brain was seen as the main antagonist in Metroid, Super Metroid and Metroid: Zero Mission. She is also seen in a flashback during Metroid: Other M, and her consciousness was responsible for the events of that game as well. In the Japanese website for Zero Mission, she is given the title Mad Overseer.

Physical Appearance

Mother Brain resembles a human brain, though she is more spherical in shape. She has short metal spikes protruding from the top of her scalp, and a single large eyeball with an iris colored differently in each game she appears in. Her appearance differed slightly in the original NES version of Metroid, where she possessed tusks and a pair of eyes; coupled with a long cable extending out of a mouth-like orifice, her facial features resembled that of an elephant. The brain was also a bright red. 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 protected by multiple Cannons, Rinka, and Zebetite barriers which serve as both protection and energy resources. She will pulse faster as she takes damage.

In Super Metroid, she has a number of changes. The artificial life-form now possesses an overall orange color and appears to be more mechanized. Her eye is now white and has no iris (although in Metroid: Other M she has 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 a forced disconnection from her capsule's life-support systems. The body itself stands taller than Ridley and is capable of multiple 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: Other M makes various changes to the depiction of Mother Brain in the beginning flashback. Firstly, she is much more skeletal than the Super Metroid version and less squat. The brain is now smaller in comparison to the body, which seems to lack the lumps present in the Super Metroid version. Her arms also seem to be longer, and her back growths appear to be slightly different.


Metroid Manga

In the Metroid manga series, Mother Brain begins as an ally of the Chozo and makes her first appearance as a small, flying monitor system. The Chozo use her to control several machines, as well as keep track of data and reports. She meets Samus Aran for the first time when the recently orphaned child walks in on a conversation between Old Bird, Grey Voice and Mother Brain. After coldly staring at a frightened Samus, Mother Brain quickly disregards her as a weak, inferior creature that will not last for more than a few days on Zebes.

During the years that went by after Samus was infused with Chozo blood, Mother Brain monitors her training and gives advice on using her Power Suit efficiently, though with a hint of mockery towards the young girl. Later on, when Samus withholds herself from killing a number of disarmed Iona Faria that had been "corrupted", Mother Brain orders Work Robots to incinerate them instead; this seemed to be a deliberate act to purposely anger/taunt Samus.

The manga shows Mother Brain's frustration with the Chozo and with the many raids of the Space Pirates. At some point, 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 universe. She designated herself as master, while giving Grey Voice, Ridley, and Samus Aran the role of Space Pirate commanders, though Samus refused to cooperate.

Mother Brain stated that she was the one who created Samus's Power Suit, and also claims that the Metroids as being her and the Chozo's children.

After it is revealed that Grey Voice was only pretending to be a Space Pirate commander in order to win Mother Brain's trust and get close to her, he begins his counterattack, claiming that even though he will allow the Pirates to have the planet, he will not permit a "defective" product to continue existing. Grey Voice soon destroys her Zebetite shield, but cannot continue his attacks when Mother Brain is rescued by Ridley, who comes and battles with Grey Voice.

Later on, it comes to light that Mother Brain is in fact using the Pirate forces to further her own goals. She plans on having them fight the Galactic Federation until both organizations become sufficiently crippled, at which point she will "cradle" the survivors to "sleep" and, after resetting the universe to zero, help them reach an intellectual level that she deems worthy of deserving life, thus giving order to the universe. She also 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.

Metroid/Zero Mission

In the NES Metroid, Mother Brain is the final boss in the second to last room of Tourian. She appears as a large, red brain within a glass stasis tank protected by the regenerating Zebetites, the infinitely spawned Rinkas and the randomly-shooting Cannons. The brain itself does not attack in any way after the tank is broken, unlike in the remake Metroid: Zero Mission. After Mother Brain has been destroyed, a self-destruct sequence begins, and Samus is forced to evacuate Zebes immediately. The manual for Metroid was the first to state that Mother Brain is the leader of the Space Pirates, which would mean Ridley is under her command.

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 Cannons. 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 Laser Brain Attack 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 (two in Easy Mode), 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 has a few minutes to evacuate Tourian before the facility self-destructs, but she is ambushed by Space Pirates as she flies in her ship outside of the planet's atmosphere. 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 (now in ruins) after acquiring the fully powered suit reveals a hidden chamber underneath Mother Brain's capsule that was also present in Super Metroid. The pools of lava have also been replaced by an extremely corrosive green chemical, the only substance in Zero Mission capable of harming Samus while she is wearing the Gravity Suit.

Metroid Prime 3

In Metroid Prime 3: Corruption, it is revealed that the Galactic Federation builds and uses organic super-computers known as Aurora Units that share many similarities to the Pirate leader, Mother Brain. These constructs are seemingly organic, neuron masses encased in metal plates floating within a tank, making the AUs also resemble giant brains confined in jars. Both Pirate leader and Federation constructs are employed as computers to navigate in a large digital network and process enormous amounts of information, as well as keeping their users constantly up to date on current events; the manga indicates that Mother Brain can link up the Federation and Chozo information databases, not unlike AU 217.

The final boss of the game, Aurora Unit 313, is an AU gone rogue. Following this change of personality, the Space Pirates seemingly granted it additional attributes that correspond to Mother Brain's, such as nearby turrets firing Rinka-like projectiles, an ocular organ-like device that fires a purple laser, and a cable supporting 313, foreshadowing Mother Brain's neck in Super Metroid. The Aurora Unit 313 theme is an arrangement of Darkness, Dark Samus' theme, arranged to resemble Mother Brain's theme in Zero Mission.

Also, prior to the release of Metroid Prime 3: Corruption, a trailer showcasing the Aurora Units featured blueprints for a "future Aurora complex" which bears a near-identical resemblance to Mother Brain's room in Super Metroid. While there is currently no official word on a possible connection between Mother Brain and the Aurora Units, a few theories have been formulated to explain all of the existing similarities, which can be found here.

In Metroid: Other M, it is believed that an advanced model of the Aurora Unit took place as MB's original infrastructure.

Super Metroid

In Super Metroid, Mother Brain is once again the final boss, living in the last room of the new Tourian base. The first part of the battle against her remains roughly the same as the NES game, consisting of shattering the glass (though now requiring several Missiles) and shooting the brain while dealing with her security systems. 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 connected to a mechanical body that was seemingly hidden underground, possibly built by the Space Pirates, indicating that she had learned from her mistakes in her last encounter with Samus.

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, as well as severely injuring Samus to the point where she can no longer stand. Just as Mother Brain is about to finish her off, the Baby that Samus found on SR388 latches itself onto Mother Brain and absorbs both her life energy and the destructive energy from her Laser Brain Attack, seemingly causing her death. The Baby then latches onto Samus, transferring the energy it acquired from the Brain to Samus. However, the Pirate leader, using an unknown method, somehow reactivates and stands back up (though badly injured), and angrily attacks the Metroid as it's reviving Samus. As the Metroid lets go of her and lunges at Mother Brain once more, Mother Brain delivers a killing blow, and the remains of the Baby fall over Samus. At that moment, Samus activates the Hyper Beam that was seemingly forged from a combination of both the stolen energy and the Baby's remains. Afterwards, Mother Brain's body is destroyed, causing her head to fall for the last time. Mother Brain's head then weakly opens its mouth and finally turns to dust. Afterwards, a Countdown starts, 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, the super-computer originally created by the Chozo has been eradicated from the universe, and its resurrection is unlikely.

In the Super Metroid comic, Mother Brain tried to convince the Baby that she was its mother, not Samus, though failed horrifically. When Chief Hardy accidentally killed the Baby, Samus was enraged. Believing that Mother Brain was its killer, Samus killed her.

Metroid: Other M

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 Laser Brain Attack. It then explodes over Samus into many small particles, resembling a rain of snow. Mother Brain then moves to destroy Samus, who whispers "We've jumped the shark" and finishes her off with the Hyper Beam on a skateboard.

Later in the game, when Samus learns that Metroids were being propagated on the BOTTLE SHIP, she questions if the scientists recreated Mother Brain. "Madeline Bergman" clarifies that they modelled a large, featureless brain after the Mother, codenamed "MB".

Near the endgame, the real Madeline states that the woman Samus encountered before was actually MB in an android form. MB's first form (the aforementioned brain) was originally used to control the Space Pirate Special Forces, while her second (more humanoid) form was necessary to perfectly control the Metroids. However, MB went rogue and seemingly generated the original Mother Brain's personality. The brain MB is destroyed by Adam Malkovich in detaching and blowing up Sector Zero, and the android MB is killed by Samus, Madeline and the arriving Galactic Federation Army.

Super Smash Bros. for Nintendo 3DS and Wii U

Mother Brain as an Assist Trophy in SSB4.

On February 7, 2014, Masahiro Sakurai posted this image on Miiverse and confirmed that Mother Brain will appear as an Assist Trophy in the fourth Smash Bros. game. Though the screenshot only showed her on the Wii U, she is featured on the 3DS version as well. Her appearance is taken from Zero Mission, where she appears onstage in her Control Capsule with Rinkas flying around. She uses the Laser Brain Attack from Super Metroid, possessing a quicker firing rate but shorter range. Use of the Attack causes the Capsule to break. Mother Brain charges and fires the beam (which retains its sound effect from Super Metroid) twice, aiming it toward the ground. Mother Brain can also turn in her capsule to aim at opponents accordingly. Before she disappears, she seems to bounce, or "nod" at the summoning character. Mother Brain can be killed, with her trophy description quipping that it will not trigger a countdown as tradition.

Fanon Appearances

I ain't got anything to add, do you?


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).

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.

The Metroid: Other M official website states Mother Brain is the true leader, as well as the game and instruction manual themselves where it is mentioned several times.

Another possibility is that, while Mother Brain controls all of Zebes, she has assigned some of her more powerful minions to be the leaders of certain parts or weaker minions on Zebes, such as Draygon controls Maridia and the Evirs, Phantoon and all the ghosts on the Wrecked Ship, Kraid in Brinstar, and put Ridley in charge of the space pirates, meaning she controls the pirates through Ridley, making him the pirate leader and still a servant to Mother Brain.


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