Mother Brain
Mother Brain ZM




Metroid (1986)

Console of origin

Nintendo Entertainment System


Mother Brain



Mother Brain (マザーブレイン, Mazā Burein) 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.


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 Ring Beam Units, 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 MangaEdit

Mother Brain was created by the Chozo to oversee planet Zebes and to bring species of the Milky Way to harmony. Mother Brain is introduced as a benevolent robot designed to protect the Chozo through Zebes. As the Chozo reveal an infant Samus to Mother Brain, Mother Brain assesses that her human body will not be able to withstand Zebes for more than a few days. Because of this, the Chozo infuse their DNA with Samus's, allowing her to survive in Zebes's dangerous environment. As revealed in the Iono Feria incident, Mother Brain assesses dangers and suggests the Chozo to act accordingly.

It is also revealed that Mother Brain oversees the development of the Chozo's Metroids. She gives them a report on their progress toward clearing the X on SR388.[5] Old Bird, Gray Voice, and possibly other Chozo were working with Mother Brain to create the Metroid species to defeat the X. Upon revealing Metroids to other Chozo, however, Space Pirates attacked Zebes, expelling the Chozo from the planet. It is likely that Mother Brain was already part of the Space Pirates and had called them as the completed infant Metroid was available. After the Chozo were removed from Zebes, Mother Brain had assumed control of at least the Zebesian Space Pirates and had given them the gift of the bio-weapon, the Metroid.

Mother Brain's creation purpose, to bring together the Galaxy's species, had backfired. Instead, Mother Brain and Gray Voice sought to organize the species through the force of the Space Pirates. The manga reveals that Mother Brain has at least Kraid and Ridley underneath her command. Mother Brain attempted to use Samus's power alongside the Pirates', attempting to persuade her by claiming that she was the parent Samus's Chozo half. Samus, however, rejected the thought of helping Mother Brain. Mother Brain is betrayed by Gray Voice and he is about to destroy her, but she calls on Ridley for help. Gray Voice reveals that Mother Brain in fact fears that Samus will grow powerful enough to destroy Mother Brain, a feat realized by Samus after years pass.

At the end of the manga, Samus approaches Mother Brain after defeating Ridley. It is left ambiguous, unclear as to whether or not Samus defeated Mother Brain or not. Because the final chapters of the manga seem to reflect what happens in Metroid, it can be safely assumed that these events are the same events in Metroid with much less detail. This means that Samus did defeat Mother Brain, which then rebuilt herself for Super Metroid.


In Metroid and its remake, Mother Brain is the main antagonist of the game. It is located in Tourian, and controls all Space Pirate actions on the planet, including Kraid and Ridley. Mother Brain's room is protected by turrets and Rinkas. Samus makes her way into Tourian, and manages to destroy Mother Brain, activating a time bomb which destroys the facility. Mother Brain is protected by a glass made of Zebetite that is very resistant to Samus's Power Beam. Samus, however, can break it by using Missiles. Once it breaks, Samus can attack Mother Brain freely until it is destroyed.

Metroid: Zero MissionEdit

Mother Brain's Zero Mission appearance is identical to her appearance in Metroid. The room is still full with turrets and Rinka and there is still a classic setup with Mother Brain at the left of the room in her Zebetite shield. Samus can now break the shield with Missiles or Super Missiles. There is additionally a lot of lava around the floor and a much larger area around. There are three platforms which Samus can use to stand on and attack Mother Brain from. Once Mother Brain is destroyed, Samus must escape to her gunship in time. Unlike Metroid, Samus can return to Mother Brain's chamber after receiving the Legendary Power Suit. Even with Samus's Gravity Suit, the strongest suit available in the game, Samus still receives damage if she touches residual acid left behind in Mother Brain's chamber. The only reason to return to Tourian after acquiring the Legendary Power Suit is to find a couple of additional Suit Expansions.

Super MetroidEdit

In Super Metroid, Mother Brain takes all the roles of the previous game, but Mother Brain transforms after her initial defeat in her Zebetite tank. She takes on the form of a highly powerful bipedal being. She also possesses the Hyper Beam. It is actually impossible for Samus to defeat Mother Brain; only the appearance of the infant Metroid allows Samus to complete the boss fight.

Metroid: Other MEdit

Mother Brain appears in one of Samus's many flashbacks. In this specific flashback, Samus is reliving her climactic encounter with Mother on her second mission to Zebes. The Metroid Hatchling heals Samus and then is destroyed by a Hyper Beam above her head. During the events of Other M, Galactic Federation scientists develop a program based on Mother's artificial intelligence and create an android known as MB. MB develops Mother's consciousness and becomes violent, stirring the creatures aboard the Bottle Ship into a frenzy, which forces Madeline Bergman to send out the distress signal that leads Samus to the facility, a much different version of events than is told by MB, who assumes Bergman's identity upon meeting Samus. MB is eventually killed through the combined efforts of Bergman and Galactic Federation troops.