Metroids are a genetically-engineered species, created by the Chozo.

By the time the games’ begin, Metroids exist on two planets: SR388 and Phaaze. The log data in Metroid Prime Trilogy establishes that the Metroid creature in the Tallon IV Leviathan had been there since it was ejected from Phaaze.

The Chozo had a buried laboratory beneath SR388, and there were remnants of battle armour on Phaaze.

The Elysian observatory confirms that the Chozo were very aware of Phaaze. They learned that planets can be alive.

Living planets can imbue information from more intelligent life, as shown when Phaaze is implanted with an Aurora Unit.

The arc of all the games ends with the destruction of SR388.

SR388 resists Samus for the entirety of her time on the planet. The geology shifts and changes, and seems to guide her into confrontation. The ocean of acid that floods the world shifts in precision response to Samus’ presence and progress. To echo the revelation of a living planet in Metroid Prime III, we could also consider whether SR388 is too a living world.

The War in Heaven – The First Living Planet

The painful birth of Metroid Prime, and its hunger for revenge

The War in Heaven – The Second Living Planet

The Revenge of SR388

The Revenge of Phaaze

The End of the Renaissance

The raids of K-2L and Zebes

The Galactic Federation discovers SR388

Original Post:The lore of the Metroid saga is rich and ancient, and full of vengeance. The story really begins tens of thousands of years ago, with an avian race of prophetic poets fighting a war throughout the cosmos. The Chozo – the dominant species in the pre-history of the Metroid universe - gaze into possible futures, invade living worlds, and engage in massively misguided genetic engineering to fight against the horrors of evolution. The primitive human race remains wholly ignorant of this war in heaven, emerging from their caves with no clue that humanity will be the final victors.I’m going to explore this rich history - this Chozo war that continued long after the species extinction. There will be references to the games, and a healthy amount of speculation to try and fill in unresolved story gaps – of which there are a lot of. You can consider the piece to be either a makeshift timeline illustrated with fanart, or just one fan’s attempt to reconcile the series continuity.Before we begin, let’s briefly revisit the following lore:And let us consider one hypothesis:With that idea, let us begin.On an unknown planet in the universe, a race of avian humanoids evolves. The species that will come to be known as the Chozo possesses great strength, agility and intelligence. The species is peaceful, and is driven by a social/religious value that nature is sacred.Certain individuals a born with a unique gift – the vague comprehension of events set to take place in the distant future. Driven by these prophecies, the race advances quickly and becomes space faring. With abstract predictions of a hostile universe, the Chozo develop powered armour and armaments to defend themselves.The Chozo discovered that - despite their prophets’ visions of a chaotic and warring universe – the galaxy was at peace. First contact was made with a number of races, such as the Ylla , the N’kren , the Bryyonians and the Luminoth . The species shared their cultures and technology, and gently colonised wild worlds such as Aether, Elysia, and Tallon IV.Throughout this galactic renaissance, the Chozo prophets continued to receive increasingly severe visions of chaos. They foresaw a universe consumed by war, of horrors evolving on distant worlds and a great toxicity waiting to infect the universe. As the visions became more precise, the species began to isolate itself from its allies, and became intensely driven to fight this unclear threat.The Chozo needed more potent tools to locate the unseen danger. They expanded their SkyTown colony on the gas giant Elysia, remaking it into a vast interstellar observatory powered by the planet’s endless storms. The facility was of such scale that an entire species of artificial life was necessary to maintain it. The Chozo created their first species – the mechanical Elysians.Probes were launched across the universe, and the Elysians and Chozo scrutinised the data. The search took generations, and the planet’s tempestuous atmosphere took its toll on SkyTown, weathering the station. Eventually a partial transmission from a decaying and distant satellite, set prophecy in motion.The data received was terrifying. The blue planet registered as an organism, somehow existing as both mineral and flesh. Impossible radiation pulsed from the surface, which overwhelmed the satellite and rendered it inert. The location of the planet was lost, and only a broad region of space could be established.The Chozo reconciled this discovery with their prophecies. On this planet of poison, could a creature have evolved so vicious, that it endangered the universe?The Chozo left SkyTown, leaving the Elysians to continue monitoring the stars for the rogue planet. The facility continued to decay around them, and they tirelessly searched until their technology became inoperative.For the Chozo, finding the deadly planet became a priority. A ship was dispatched to the dark corner of the universe where their satellite had been lost. Their best warriors, scientists and prophets, knowing that they may never be coming home, voyaged for the hostile world.After generations, the descendents of the original Chozo crew finally found the planet. Their scans confirmed their worst fears – the cauldron of radiation and mutation had produced devastating creatures. If these monsters somehow escaped their containment on Phaaze, they could devastate the universe. With younger races such as Humans and Zebesians only centuries away from space travel, the Chozo could not risk them finding this world and releasing its terrors.The Chozo expedition was at an impasse. The threat needed to be neutralised, but severe action against the planet would be sacrilege. The Chozo hold life sacred, and could not destroy the planet.(Artist:A dangerous plan was agreed. The ship landed on the planet, exposing the crew to tremendous radiation. Chozo warriors in power suits fought the planet’s creatures as they approached the ship, watching their kin die around them, in a desperate mission to buy time.The scientists within the ship harnessed the intense radiation of the planet and tried to engineer a predator that could neutralise the worst creatures. With access to the unique Phazon mutagen that covered the poisonous world, genetic engineering that should have taken decades was done in days. The Chozo engineered the first Metroid.The creature was unleashed onto the planet, and the radiation caused it to reproduce quickly. The resulting swarm of Metroids consumed the planet’s monstrosities and established themselves as Phaaze’s apex predator.The Chozo mission was complete. The worst creatures had been neutralised, and without a food source the Metroids should also starve and expire. The cost had been enormous – most of the crew had been killed defending the ship, and the survivors were deathly ill from radiation poisoning. The burnt and damaged ship took off for the long journey home, but the crew soon succumbed to the radiation they had endured. The autopilot took the ship of Chozo bodies home.On Phaaze, the Metroid creatures proved to be more adaptive than planned, and sustained themselves on the endless radiation. The corpses of Chozo warriors were absorbed into the planet, and their battle armour became slowly weathered and scattered. The planet’s slow sentience developed an outrage that seethed under its continents. It had been violated by the Chozo. It developed a very primitive concept of purpose and retribution.Over decades, Phaaze established a vague awareness of concepts it had absorbed from the brains of the Chozo warrior corpses – and the location of two worlds from the Chozo’s memories. As the planet entered its reproductive cycle, it purposely directed two of its seeds towards the planets Tallon IV and Aether. In the seed sent to the Chozo world, Phaaze included a single Metroid creature and some ruined pieces of Chozo armour – intended as a reminder of the crime it had endured.The expedition ship – heavily damaged by radiation and lack of maintenance – was guided back to civilisation by an increasingly eratic auto-pilot. After decades it eventually approached the Chozo world of Zebes, and crash-landed onto its surface. The Chozo civilisation attempted to recover its data logs with very limited success – they were able to understand the sacrifice that the heroic crew had made, and confirm the apparent success of the Metroids in neutralising the creatures on the living planet. The Chozo authority were not able to establish the location of Phaaze, or recover much in the way of scientific data concerning it.As the Tallon IV seed began its centuries of travelling through space, the lone Metroid within absorbed vast amounts of Phazon and radiation. It became self-aware, and grew in size, intelligence and strength. It used the ruined pieces of Chozo armour to construct itself an exoskeleton, and descended into madness. It resented Phaaze for imprisoning it in the Leviathan, and resented the Chozo for creating and discarding the Metroids. It decided that it would survive, bring order to the chaotic universe that birthed it, and somehow enslave Phaaze to its will. In its solitude, it plotted its revenge.With a clear understanding of the danger of living planets – the Chozo authority began to look for any other similar threats. With more advanced technology than they had during the Elysian era, they were unfortunate enough to find one.The Chozo detected a world in a dark corner of the galaxy, so obscure that it didn’t have a name. The planet was codenamed SR388, and satellites picked up strange qualities – though seemingly mineral, the caverns and liquids beneath the surface shifted with metabolic pace. A ship was dispatched, and the strongest Chozo warriors braved the caverns beneath the surface.Few made it back. They told of a cauldron of evil, an environment so hostile and vicious that it had birthed the most terrible things. Beneath that planet, evolution had been won by a parasite that could steal the flesh, abilities, memories and strengths of all of its prey. If this creature somehow gained access to the wider universe, no force could contain it. At this stage, it was unclear if the planet was alive or not.The threat had to be dealt with. Remembering the apparent success of the Chozo expedition to Phaaze, a plan was put into action. The Chozo assembled their best and brightened, their strongest and wisest. They carved their way into SR388, and dispatched mechanical creatures to construct secure facilities. Robots and Chozo warriors dispatched all instances of the X-Parasite as they found them, but casualties were high. The planet fought the Chozo at every turn, drowning them in acid and unleashing ambushes of creatures.Deep in the planet, a glass laboratory was created, its walls highly resistant to SR388’s acid belly. Here, in proximity to the X-Parasites, the Chozo scientists began their work.The Chozo tried to recreate the plan of their ancestors – the use of Metroids to pacify creatures too dangerous to exist. Without access to the same planetary radiation and materials the Phaaze expedition had, progress was slow. As the war against the planet was raging around them, the Chozo scientists were able to engineer Metroids, but not a variant strong enough to overcome the X-Parasites. As more and more Chozo died protecting the laboratory, a different approach was needed.The Chozo succeeded in creating a Metroid Queen, who would deposit Metroid Hatchling eggs. When grown this way, the resulting Metroids were strong and durable creatures, and able to feed off the energies of the X-Parasites with ease.The scientists collected Hatchling Eggs and the surviving Chozo warriors distributed them across the planet. Soonafter the eggs hatched, and the X-Parasites were immediately overwhelmed by the infant Metroids. The X-Parasites were quickly hunted to near-extinction, with only a few surviving cells entering a state of suspension deep in the planet.The Chozo had won their war, but only just. Most of the warriors and scientists had not survived, and those that were left had to make sure that the X-Parasites had been permanently suppressed. The planet shook with tremors – the earth shifted and acid poured, as if the world was trying to crush the Chozo in their glass laboratory.The X-Parasites did not return, and the Metroid Queen continued to scream as her prison shook. The Chozo didn’t realise it, but her despair was being heard.SR388 had been violated by the Chozo. Though very different to Phaaze, SR388 had its own vague sense of awareness. It perceived the Chozo as a viral infection, and the dead X-Parasites as part of itself. It understood loss, and shook with ancient rage.It changed itself to change the Metroids. It adopted them to replace the X-Parasites, and quickly killed the weaker breeds. It moved its radioactive minerals closer to their eggs and soon mutated the species. As SR388 had done with X, it did with the Metroids. It made them strong.Alpha, Gamma, Zeta and Omega Metroids spawned quickly, and responded to the screams of their Queen. With their bulk and strength, they smashed through the glass laboratory and slaughtered their Chozo creators. The Chozo warriors were hunted down and crushed.SR388 developed into a new cauldron of hostility. The Metroids served as the Apex predator, and the robots of the Chozo deteriorated into machine madness and prowled the ruins killing on sight. The Chozo mission to suppress the X-Parasite had been a success, but the planet had gained its revenge.The Chozo had devastated two planets for the good of the universe, and sustained many causalities. The superpredators of Phaaze were extinct and the X-Parasites were apparently gone forever. With the emergency over, the race became consumed with a collective sense of guilt over their necessary actions. The Chozo believed the life of the universe to be sacred, and had to reconcile their aggressive actions with their faith.Worse still, their prophets continued to have visions of endless battles and death. War was coming to the universe, and it seemed that their sins had not saved them. Some began to doubt these visions. A schism occurred. Some Chozo colonies remained involved with universal affairs, to try and help prevent the prophesised war.The bulk of the Chozo civilisation retreated to the colony on Tallon IV. Technology was shunned, and a simpler, poetic life began. The Chozo reconnected themselves with the natural world and tried to live in harmony with it. The prophets tried to warn their fellows of a great poison that was to come, but these visions were met with increasing dismissal.The day finally came when the prophets were believed.Phaaze’s seed crashed into the new homeworld of the Chozo, and it brought poison and death. The impact survivors watched as their sacred nature succumbed to the mutagens leaked from the seed, and were hunted as the flora and fauna became deadly. Phazon spread beneath the surface of the dying planet, and radiation levels started to rise.The Chozo’s punishment for their sins, and the fulfilment of Phaaze’s wrath, reached biblical proportions. The Chozo of Tallon IV did not get to rest in peace. Their life energies suffered from Phazon disruption, and upon death they became mad ghosts who screamed forever as they were torn in and out of the material world. In this purgatory, the undead immaterial Chozo murdered anyone they could find.As their numbers dwindled, the last of the Chozo constructed a great temple above the impact crater. Within this temple, they used what little technology remained to project an energy field around the Leviathan to slow the scale of contagion. As the Chozo civilisation on Tallon IV was extinguished, their dying prophets told of a hero who will one day emerge, to enter the crater and defeat the evil worm within.Within the Impact Crater, Metroid Prime remained trapped behind the Chozo energy field, in an armour made from the remains of ancient Power Suits, waiting for its own revenge.Tallon IV and Aether were both devastated by Phaaze’s revenge. The Chozo and Luminoth were now endangered species, with only small colonies escaping the devastation. Without the help of the Chozo, the Elysians fell into disrepair and machine madness. The Bryonnians sustained a cataclysm, the nature of which is unclear, but soon devolved the race to a bestial existence. The Alimbics ascended to a higher plane of existence, and the Diamonts mysteriously disappeared. The alliance of the old races was dead.On the planet Zebes, the prophets of a small Chozo settlement have visions of the inheritor of their dying race. They see a human woman in orange Chozo armour, and build murals to herald her coming.Centuries passed and the younger races of the universe – the Humans, Space Pirates, Vhozons, Krikens, Jovians, Phrygisians and others - became space faring. They discovered that they were in an old and vengeful universe, surrounded by ruins, and that the past had many secrets.K-2L was a human colony in which the young Samus Aran lived with her family. The Space Pirates raided the colony and murdered everyone she ever knew. With this act, the Space Pirates quite incidentally created their nemesis.A nearby small Chozo settlement on the planet Zebes picked up the colony distress signal and sent a ship. They found Samus to be the only survivor of the massacre. Samus was adopted by the Chozo, and the begin to recognise her as their inheritor, the woman who will wear the orange armour as prophesised.They raise the girl as one of their own, and train her in exploration, technology and combat. They foresee she has an important future, and do everything they can to equip her for it.Samus leaves the colony, and during her absence, a Space Pirate raid takes place. Samus discovers that her second family, have been murdered in the same manner as her first. She is alone in the universe.Events are escalating. The Galactic Federation discovers the dark planet SR388. The planet perceives the human presence, and has a clear awareness of the devastation caused by the last strangers who invaded. Rather than flood the invaders with its acid oceans, or corner them into an ambush, SR388 apparently allows the scientists to take some young Metroid organisms.As SR388 has spent centuries honing these creatures into perfect killers, it perhaps allows the young hatchlings to be taken, so that they can grow and kill all strangers beyond the stars. The planet’s revenge against an outside universe, that refuses to leave well enough alone.The Metroid hatchlings that have been taken, will be soon stole by the space pirates and ignite a war across the stars. SR388 has unleashed havoc across the universe.