Mother Brain
Mother Brain is the main antagonist of Phantasy Star II. It is a computer system designed to transform the deserts of Mota into a green, habitable land, but has been corrupted by an unknown destructive force.


When Earth became uninhabitable, several humans built the spaceship Noah and escaped into space. For years, they traveled the universe until they discovered Algo. They decided they wanted it, but they needed to get rid of the native population first. Mother Brain was created in order to fulfill that purpose.

Mother Brain established itself as a benevolent being only concerned with making life better for Algo. Under Mother Brain, luxuries that were once beyond the reaches of all but the richest of men were now commonplace. This confused the people, who were not used to such things, and they began to fight for what was created. Mother Brain fulfilled every dream and desire of those it watched over, making it so that no one needed to work anymore.

Unbeknownst to the population, there was an insidious purpose behind this. Because no one was working anymore, the people had become weak and lethargic. In time, they began to believe that they needed Mother Brain to survive. It was the intention of Mother Brain to lead Algo down the path of destruction once the people became completely dependent on the system.

Only Lutz, the magician who had helped Alis defeat Lassic, suspected Mother Brain's real purpose. He fled to Dezo, where he and the espers built a mansion. He put himself into cryogenic sleep, knowing that there would be need for his help in the future.

In time, Mother Brain took over planning and controlling all aspects of the environment. The system quickly spread to Mota, where it turned the once arid planet into a lush grassland capable of growing crops. It was never able to become widespread on Dezo, however, because the Dezolians distrusted computers.

In space century 1274, there was a collision of spaceships above the Dezo Spaceport. There were no survivors on either ship apart from Rolf, whom Lutz saved when he heard Alis's cry. Mother Brain used the incident to ban all space travel, effectively cutting the planets off from each other.

Eight years later, Neifirst escaped from the Biosystem Lab, stealing DNA data in the process. She escaped to Climatrol and began using its energy to create biomonsters. Mother Brain was unable to stop the creation of these monsters, thus forcing the Commander of Mota to have Rolf investigate the source of the problem.

When Climatrol was destroyed, all the spare rain supply poured into the river, causing mass flooding. The government of Palm blamed Rolf for Mother Brain's malfunctions and sent a robot army to hunt them down.

When Rolf and the others were sent to the prison satellite known as Gaira, Mother Brain saw a way to kill two birds with one stone. It damaged the satellite, causing it to fall out of its orbit straight for a head on collision with Palm. It managed to realize part of this goal with the destruction of Palm, but a space pirate named Tyler managed to rescue the group before the impact.

Much later, after Lutz revealed the true purpose of Mother Brain, Rolf and the others were transported to Noah

Mother Brain

in order to destroy the system and free Algo. Upon reaching the computer system, they were confronted with a hologram of a beautiful woman. The system made no secret of its true purpose, but warned that without her, the people would become helpless and die. However, Rolf and the group engaged her, knowing that she would now only do more harm than good.

In battle, she fires a beam that does damage to all party members or, less commonly, a single member. She is considerably easier than Dark Force, the boss that immediately precedes her. She was ultimately destroyed.


The death of Mother Brain ushered in a period of decline known as the Great Collapse. Over 90% of Algo's population died, and the advanced technological culture was lost. In the aftermath, scientists on the planet Mota attempted to build a new Mother Brain unit code-named Daughter. However, the plan was abandoned and it was later decided to build a enviromental control system on the satellite Zelan, watched over by a Wren-unit andriod.

Phantasy Star Universe

A enemy boss named Mother Brain appears in the AMF HQ in Ambition of the Illuminus. It attacks with its arms
and by shooting shockwaves that travel along the floor and damages the player and can protect itself with a force field. It bares some resemblance to Mother Brain's holographic form, but it is safe to assume that it is a separate entity than the one that appears in Phantasy Star II. 

Phantasy Star II
Playable Characters Rolf - Nei - Rudolph Steiner - Amy Sage - Hugh Thompson - Anna Zirski - Josh Kain - Shir Gold
Antagonists Neifirst - Army Eye - Dark Force - Mother Brain
Planets Mota - Dezo
Locations Paseo - Arima - Oputa - Zema - Kueri - Piata - Zosa - Aukba - Ryuon - Esper Mansion
Dungeons Shure - Tower of Nido - Biosystems Lab - Roron - Uzo Island - Climatrol - Control Tower
Red Dam - Yellow Dam - Blue Dam - Green Dam - Gaira - Skure - Crevice - Menobe - Guaron - Ikuto - Naval - Noah