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‘Defective product’.... Me...?!! A defective product... You dare claim that I am defective...!!

—Mother Brain[2]

Mother Brain (マザーブレイン Mazā Burein?) (Referred to simply as Mother in the opening of Metroid: Other M) is a recurring antagonist and 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 (狂気の支配者?).

Physical appearanceEdit

Metroid Boss Mother Brain

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. When she is only one hit away from defeat, she will stop pulsating altogether. In Metroid: Zero Mission, although otherwise resembling her appearance in the NES, she possessed a single eye (which the cutscene shown after Samus first boards an elevator reveals it to emerge from the body itself), with it also possessing vertical flaps that causes it to have a more slitted appearance.

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.

Abilities and personalityEdit


MotherBrain drool

Her body appears to be based on Chozo technology.

Mother Brain's role has been mostly vague in the Metroid series. There is debate as to whether she or Ridley is the supreme leader of the Space Pirates, with this question growing more confusing 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. Additionally, 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 group's presence has only been mentioned during the time of Mother Brain's inactivity and as such, High Command itself may or may not be subservient to her.

Media outside of the Metroid series often describe Ridley as the highest ranking member of the Space Pirates. Some of the latest Metroid games, such as Metroid: Other M (its instruction manual, official website and in-game) along with the prologue cutscene in Metroid: Samus Returns, state that Mother Brain is the true leader.


Several sources in past media, along with Metroid: Other M's portrayal of MB's abilities, imply that Mother Brain can influence/control her Pirate forces and wildlife with telepathy. This may explain why a large portion of the native flora and fauna on Zebes are highly aggressive toward Samus, as the Pirate leader is directing them against her. The first mention of her psionic abilities in media appeared in the Nintendo Comic System story: The Coming of a Hero, in which she is shown to display mental control over the Metroids.

Samus states in Other M that Mother Brain's telepathy is the only thing that can control Metroids; however there is proof that she does not have complete dominance over them, making this method of control arguably far from perfect. Circumstantial evidence that supports this is the cutscene that plays in Zero Mission when Samus enters Tourian, which clearly show Metroids having escaped and killing all Pirate personnel despite being near Mother Brain; absolute control over the species would have otherwise resulted in the Pirates fighting alongside their specimens against Samus. The loss of control may have happened once more in Super Metroid, as specimens are seen roaming freely in numerous rooms within the rebuilt Tourian. Whether or not the Metroids broke free on their own is unclear as well: despite no in-game evidence, if one considers Mother Brain's rather cold and malevolent disposition seen in other media, she might have intentionally released them to eliminate Samus at the Pirates' expense.

She is also completely unable to control the last Metroid, at least in its Big Metroid form. In the Super Metroid comic, the baby rejected Mother Brain as it believed Samus was its mother, further proof that she could not perfectly control a Metroid, though the comic may be deemed inadmissible as it is not canon to the game's events in the timeline. Further evidence is that the scientists on-board the BOTTLE SHIP turned to the creation of MB's humanoid form in the hopes that newly born Metroids would imprint onto her, thus recreating the bond that occurred between Samus and her baby.


Metroid mangaEdit

Vol2 page13

Mother Brain's flying monitor system. Mother Brain can monitor Zebes with its camera eye and communicate through it.

In the Metroid manga published by Magazine Z, 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 Iono Feria 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 are 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/Metroid: Zero MissionEdit

Metroid 1 Mother Brain screenshot

Mother Brain as she appears in Metroid.

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.


Mother Brain as seen in 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. She appears in a cutscene that plays when Samus first boards an elevator, where her eye comes out and has Samus's image reflected on it, as well as vertical flaps closing in (implying she was observing Samus's progress). 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 a brain blast from her eye. 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. 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.

Surprisingly, Mother Brain does not appear as the final boss of the game. 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: Samus ReturnsEdit

Against all odds, Samus Aran eradicated the Metroids on Zebes and defeated Mother Brain, the leader of the Space Pirates. And so their sinister plans were thwarted... for a time.

Metroid: Samus Returns introduction

Metroid Samus Returns Mother Brain battle

Flashback of Samus fighting Mother Brain and the Metroid larvae in Tourian during her Zero Mission

While Mother Brain does not physically appear in Samus Returns, she makes a brief cameo along with Metroid larvae, Rinkas and Cannons in the introduction in a panel recounting the battle during her Zero Mission. As a result of misuse of the Metroids by Mother Brain and the Space Pirates, the Federation decided to send Samus to SR388 to exterminate the former.

It can be assumed that the reconstructed Mother Brain gave Proteus Ridley the order to interfere with Samus' mission and capture at least one Metroid specimen.

Super MetroidEdit

Mother Brain SM Flashback

Mother Brain in the flashback at the beginning of Super Metroid.

Though Ridley fails to acquire the last living Metroid on SR388, he succeeds during his second attempt in the Ceres Space Colony, and eventually brings the specimen to the new Tourian base on planet Zebes. Under Mother Brain's command, the Space Pirates begin exposing the creature to Beta-Rays in an attempt to create additional Metroids through a cloning method; the latter would produce both failed and successful clones. Under unspecified circumstances, the baby transformed into a Big Metroid, a mutation that would ultimately bring about Mother Brain's downfall in the final battle.


In Super Metroid, Mother Brain is the final boss, living in the last room of the new Tourian base. The first part of the Final Conflict against her remains roughly the same as in the original game, consisting of shattering the Control Capsule's 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. This indicates that she had learned from her mistakes in her last encounter with Samus.

SSBU Spirits Mother brain 2nd Form

Mother Brain's new body

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's Missile, Super Missile and Power Bomb reserves, 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 returns and latches itself onto Mother Brain, both absorbing her life energy and robbing her of the Laser Brain Attack, seemingly causing her death. The baby then latches onto Samus, transferring the energy it acquired into Samus. However, Mother Brain somehow resurrects herself and stands back up (though badly injured), and angrily attacks the Metroid. As the baby releases Samus 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 discovers she has a Hyper Beam that was seemingly forged from a combination of Mother Brain's stolen attack and the Baby's remains. She uses it to overpower Mother and avenge her fallen "child", destroying her body and 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 obliterate 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 MEdit


Mother Brain in Metroid: Other M just before slaying the baby Metroid.

A 3D version of the Final Conflict in Super Metroid is featured in the Metroid: Other M introduction cutscene. The baby 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 "Mother! Time to go..." and finishes her off with the Hyper Beam before escaping Zebes.

Mother Brain CA

Metroid: Other M Gallery Mode

Later in the game, when Samus learns that Metroids were being propagated on the BOTTLE SHIP, she wonders out loud if the scientists recreated Mother Brain. A female scientist clarifies that they modeled a large, featureless brain after the Pirate leader, codenamed "MB" and programmed it to reproduce the Mother Brain's thought processes.

Main article: MB
MB first form

MB's original brain form

Near the endgame, another survivor reveals that the scientist 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 unit, while her second humanoid form was created in an attempt to control the ship's propagated Metroids. However, MB went rogue and seemingly manifested a malevolent personality akin to Mother Brain's. The brain MB is destroyed by Adam Malkovich when he triggered Sector Zero's self-destruct sequence, and the android MB is ultimately killed by the arriving Galactic Federation Army.

Mentions in the Metroid Prime seriesEdit

Although Mother Brain herself does not make any appearances in the Metroid Prime series, she is mentioned and referenced occasionally.

Metroid PrimeEdit

Mother Brain is briefly mentioned in the game's manual and in an unused opening.

Ten years ago, beneath the surface of Planet Zebes, the mercenaries known as "Space Pirates" were defeated by interstellar bounty hunter Samus Aran. Descending to the very core of the pirate stronghold, Samus exterminated the energy based parasites called "Metroids" and defeated Mother Brain, the leader of the pirate horde.

But the Space Pirates were far from finished. Several pirate research vessels were orbiting Zebes when Samus fought on the surface below.

After the fall of Mother Brain, the ships escaped, with the hope of finding enough resources to rebuild their forces and take their revenge.

After discovering a possible pirate colony on planet Tallon IV, Samus has once again prepared for war, hoping to end the Pirate threat forever.

—Unused introductory monologue.

Metroid Prime 3: CorruptionEdit


The future Aurora Unit complex.

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 Aurora Unit 217.

In addition, an unused Federation Log for Aurora Unit 242 in Metroid Prime 3: Corruption indirectly refers to Mother Brain, as the character Fleet Admiral Castor Dane was mentioned in the log to be very critical of Aurora Unit 242's nickname of "Other Brain."

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.

Main article: Future Aurora Complex

Additionally, prior to the release of Metroid Prime 3: Corruption, a trailer showcasing the Aurora Units featured Galactic Federation blueprints for a "future Aurora complex", which bears a near-identical resemblance to Mother Brain's room built by Zebesians 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.

Other appearancesEdit

"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.
  • A microgame called Metroid in WarioWare, Inc.: Mega MicroGame$! and WarioWare, Inc.: Mega PartyGame$! re-enacts the fight between Samus and Mother Brain from Metroid. It is slightly different than the original fight, but mostly the same. It also seemed to retain the siren system from the Famicom Disk System version.
  • Mother Brain is mentioned in Super Mario RPG: Legend of the Seven Stars. If Mario returns to the Mushroom Kingdom castle before going off to Land's End, Samus will be sleeping in the palace's guest room bed, and if talked to, will say that she is resting up for Mother Brain.
  • In the Nintendo Comics System-published story Duh Stoopid Bomb! which contains characters from the Mario series, Mother Brain's name appears on a list of people who think King Toadstool is dumb.
  • Mother Brain appears in the background of level 12 in Marathon Mode in Tetris DS, which is Metroid-themed.
  • Mother Brain and her usage of Metroids is given an indirect reference in Animal Crossing: New Leaf via the Fortune Cookie that supplies the player with a Metroid, where the text states "Wise men say the brain is a terrible thing to waste."

Captain N: The Game MasterEdit


Mother Brain as she appears in Captain N: The Game Master

In the TV show Captain N: The Game Master, Mother Brain is the main villain. She is portrayed as a female supervillain with a human-like face, bearing little resemblance to her actual appearance ingame. This depiction of Mother Brain also appeared in the Nintendo Comics System and Captain N comic book series, as well as in an obscure German comic, where she was shown with larger, more grotesque lips.

Mother Brain's voice in the television series was provided by the late Levi Stubbs of the The Four Tops. Stubbs had previously played a similar character, Audrey II, in the 1986 version of Little Shop of Horrors. Like Audrey II, Mother Brain has a feisty and flamboyant personality. She is very power-hungry but also incompetent and easily frustrated by her slow-witted assistants, King Hippo and the Eggplant Wizard.

One comic called Nervous Meltdown depicted her perception of herself within her consciousness. Here she is represented as a woman with blonde hair, blue eyes and what appears to be a combination of a red top and shorts. She is referred to as "Little Girl". Coincidentally, MB is also a blonde-haired, blue-eyed woman wearing a sort of overclothing in red color. Also, similar to "Little Girl", at least one character wondered if MB was truly evil or if she was simply misunderstood.

Super Smash Bros.Edit

In Super Smash Bros. Brawl, Mother Brain appears as a sticker, using artwork from Zero Mission. She can be equipped to any fighter and grants Flinch Resistance.

Ssb4 mother brain

Mother Brain as an Assist Trophy in Super Smash Bros. for Wii U.

On February 7th, 2014, Masahiro Sakurai posted an image on Miiverse and confirmed that Mother Brain would appear as an Assist Trophy in Super Smash Bros. for Nintendo 3DS and Wii U. 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.

SSB Ultimate Samus vs Mother Brain

Mother Brain in Ultimate

Mother Brain returns as an Assist Trophy in Super Smash Bros. Ultimate. Additionally, she appears as an Ace class Primary Spirit who can be equipped to fighters to provide a stat boost. Much like the Sticker from Brawl, she uses her artwork from Zero Mission. She is a Shield type, giving her advantage over Attack types but disadvantage against Grab types.

Like all other Primary Spirits, she can be leveled up through battle experience, Dojo training, or snack eating; upon reaching Level 99, she can be enhanced to Mother Brain (2nd Form), using artwork of her final form from Super Metroid. This resets her level to 1, but promotes her class to Legend and grants her the Giant skill: at the start of a battle, any fighter who has Mother Brain (2nd Form) equipped will be giant.

Mother Brain's Spirit can be unlocked in the World of Light Adventure Mode, where it possesses a Dark Samus Puppet Fighter in her dark red costume. Dark Samus favors using her Charge Shot, and she is joined by Mother Brain as an Assist Trophy. The battle takes place on the Omega Form of Planet Zebes: Brinstar Depths, with Escape as the background music (presumably referencing the theme's use after beating Mother Brain in Metroid and Zero Mission). All combatants have increased power when using energy attacks.

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

Official dataEdit


Super Metroid storyboard

Metroid manualEdit

"Mother Brain lies in the central base of the fortress planet Zebes, the home of the space pirates. Its aim is to cultivate Metroid[3] to multiply and conquer space. Zeebetite is its energy source. You have to discover Mother Brain's weak point before you can launch a missile attack. When hit, it makes a shrieking noise."

Virtual Console retranslationEdit

"Mother Brain lies in the center of the planet Zebes. She plans to cultivate the Metroids and use them to conquer the universe. It's claimed that she is a massive mechanical life-form, but nobody knows for sure…"

Official Nintendo Player's GuideEdit

"This is the backbone of the fortress planet Zebes, and it is the one determined to multiply Metroid. It is Samus’ ultimate target. In order to destroy it, over 30 continuous missile shots are required."

Super Metroid interviewEdit

Interviewer: Huh? Made it dirty?
Mashita: Apparently, the characters I drew were fairly cute. Characters like Crocomire were so charming that when they were killed, the player would feel sad about them.
Osawa: He wanted to them to look like Fujiko Fujio's work! Then Yamane came into the picture.
Mashita: When that happened, the characters became harsher so that the player could defeat them.
Osawa: Fujiko Fujio became Hino Hideshi!* (Laughs)
Sakamoto: Like Mother Brain!
Osawa: At first, I drew her. Then, I made the character look like an old lady living in my apartment complex. (Laughs)
Mashita: I wanted to see a shopping bag hanging from her hands.
Osawa: Then Yamane-sensei appeared.
Mashita: After that, saliva dribbled down, she spit out foul breath, and she was filthy.
Sakamoto: Well it wasn't static as the rest was terrible, so we cut down on the amount of drool. Anyhow, in the final version, there was a moderate amount of drool. (Laughs)

Super Metroid Players' GuideEdit

Mixing It With Mother Brain (page 70)
"The perpetrator of all the trouble. Mother Brain is at the very core of Zebes, controlling all the operations on and around the planet. It will take every ounce of strength, courage and determination to make it past this heinous enemy.
Your weapons should be numerous by now, but you'll need to make a swift decision on which one to use. Will it be the super missiles or the power bombs? How about one of the beams? You're on your own now - few adventurers have ever seen the Mother Brain, let alone lived to tell the tale. But you've got this far so don't give up now!"

Metroid FAQ (Metroid Zero Mission Official Site)Edit

Game Informer 300th issue cover

Cover for the 300th issue of Game Informer.

"If the Chozo made Mother Brain, why is she so dangerous?"
Yoshio Sakamoto: "Mother Brain was not originally dangerous, and was an indispensable artificial intelligence that served as the center of the advanced Chozo civilization. However, as an extremely superior standalone AI, Mother Brain sprouted dangerous thoughts and went berserk."

Captain N: The Game Master – The Complete SeriesEdit

The Forces of ChaosEdit

"Mother Brain is part grotesquely enlarged human brain, part souped-up bionic support system, and all evil. Every electrical device on Metroid, from the robot workers in the airlocks to the TV monitors and toasters, has been wired to do her bidding. In her high-tech nest at the center of the planet, Mother Brain spins her schemes and directs the Forces of Chaos' grand conspiracy. "

The Triforce is as good as mine! Once I get rid of you potato heads, that is.

—Mother Brain

Brawl StickerEdit

Metroid: Other M Art FolioEdit

Mother Brain and the Baby MetroidEdit

"A dream - I was reliving the tragic moments of my recent past. The Baby Metroid that had emerged from its egg in front of me so long ago was protecting me from the assault of Mother Brain. It would sacrifice its life to save me, and in doing so, give me the power of the Hyper Beam that would spell Mother Brain's doom."

Miiverse postEdit

"Pic of the day. Housed within the Control Capsule! Protected by Rinkas! Eyeball armed with a Laser Brain Attack!! The massive Assist Trophy Mother Brain joins the collection!!"

Super Smash Bros. for Nintendo 3DS and Wii U websiteEdit

"Mother Brain from the Metroid series is an enormous Assist Trophy that fires vertically tracking laser rays. Fighters caught in the rays will rack up numerous hits and damage, so it's better not to be in front of her. By the way, it's possible to defeat Mother Brain by attacking her."

Super Smash Bros. for Nintendo 3DS TrophyEdit


3DS Trophy.

"Hailing from the Metroid series, this evil boss resides on the planet Zebes. When she appears in Smash Bros., she attacks with energy projectiles and a beam from her eye. It's actually possible to defeat her, and for once doing so won't start a self-destruct sequence."
"A mainstay of the Metroid series and the final boss Samus faces on Planet Zebes. In this game, she grows to a gargantuan size and fires all sorts of energy blasts at you. Good news: you can beat her! Better news: doing so won't trigger a self-destruct sequence forcing you to make your escape!"

Super Smash Bros. for Nintendo 3DS and Wii U TipsEdit

"Attack Mother Brain to defeat her! The glass around her will shatter after she fires lasers—that's your chance to strike!"

"Mother Brain will fire ring-shaped projectiles called Rinkas from off-screen. These are energy based, so they can be absorbed or reflected."

"Mother Brain will send colorful lasers shooting up and down the screen. They can't be absorbed or reflected, so you'll have to just avoid them!"

"It's totally fine to use Mother Brain to shield yourself from the attacks of your rivals."


Musical themesEdit

This is the theme of Mother Brain in Metroid: [2]

This is the theme of Mother Brain in Super Metroid: [3]

This is the theme of Mother Brain in Metroid: Zero Mission: [4]


  • Mother Brain might be a play on the part for computers, the Motherboard, as she is connected to a board-like structure. Alternatively, since the Metroid series was inspired by the Alien movies as speculated, Mother Brain's name may have derived from the main computer of the Nostromo, "Mother".
  • Mother Brain has been very well-received by the gaming community, often considered one of the best videogame villains:
    • In a PC World article, Mother Brain was voted as #6 of the top 47 "most diabolical videogame villains of all time."[4]
    • In Game Informer magazine, Mother Brain was rated #2 on their "Best Boss Fights Of All Time" list.
  • Why Zebes exploded following Mother Brain's death in Super Metroid and not in Metroid/Zero Mission was never explained. It is possible that as she was being repaired from her first defeat, she became symbolically linked to the planet, similar to how Aurora Unit 313 was linked to planet Phaaze, consequently starting a chain reaction when killed.
  • Mother Brain is one of the few beings in the entire Metroid series to officially best Samus in a battle. In Super Metroid, both Mother Brain and Ridley (at the beginning) could outmatch Samus, while an SA-X and an Omega Metroid from Metroid Fusion were also capable of bringing her to the brink of death. Finally, Dark Samus succeeded in putting Samus in a month-long coma after their first encounter in Corruption.
  • In Super Metroid, when attacked by the baby, Mother Brain crouches in a pose similar to the Chozo Statues. This may hint that the Space Pirates may have used Chozo technology to build Mother Brain's mechanical body, or it may simply refer to the fact that Mother Brain is Chozo technology.
  • Characters named Mother Brain also appear in Chrono TriggerPhantasy Star II, and Blaster Master Zero.
  • Mother Brain is the only creature known to survive having all her energy drained by a Metroid. She seemingly "resurrects" herself using unknown means, though it may be related to her bio-mechanical nature. Samus has also survived numerous Metroid predation attempts on her.
  • Although Mother Brain's plans revolved around the exploitation of the last surviving Metroid in the galaxy and went through great lengths to acquire the creature, she appeared to have no qualms with killing it when it helped Samus, thus putting an end to her own plans. It can be interpreted that, in the climax of the battle, she was determined at killing the heavily wounded Samus above all else, as this act would remove the greatest threat to the Space Pirates' existence.


For artwork, see Mother Brain's Gallery.

References and FootnotesEdit