Ra Moon crashed on Earth 20,000 years prior the events of the game. According to him, he gave humans the capacity to harbor violence towards each other, the technology and tools to further their hatred, and made them construct a temple for him. His plan was to have the humans wipe each other out and then rule the Earth with an army of his own machines. However, Ra Moon grew tired of the humans' violence and decided to delay his plans, burrowing himself underground alongside the Temple of the Moon.
Years later, Dr. Wily found Ra Moon in the Lanfront Ruins when investigating its electromagnetic field. Ra Moon analyzed Wily's computer and used its data to recreate his robots from DWN-009 Metal Man to DWN-024 Shadow Man, and assisted him in creating Ra Thor. Mega Man fought the 16 revived robots and defeated all of them, but was knocked out in the last battle against Spark Man, getting captured by Wily. Wily and Ra Moon revived all the robots again with the exception of Shadow Man, who could not be repaired. When Wily activates Ra Thor and orders him to destroy Mega Man, Ra Thor attacks Dr. Wily's robots, and Ra Moon reveals that he was only using Wily and plans to destroy Earth. Wily's robots free Mega Man and he fights Ra Thor to save Wily, destroying him. After the battle, Ra Moon says that Ra Thor was just another of Wily's imperfect machines, and shows that he had secretly created the New Yellow Devil, his appearance being on the data Ra Moon got from Dr. Wily's Yellow Devil. After a difficult battle, Mega Man manages to destroy both the New Yellow Devil and Ra Moon by firing a charge shot with the Mega Buster in both arms, also taking down the temple.
Ra Moon appears in Archie Comics' Mega Man comic series during the "Spiritus Ex Machina" arc. His role is similar to his role in the game, except that the only Robot Masters he rebuilds are from Mega Man 2 and he serves as the initial creator of the Mega Man 3 Robot Masters, based on designs made by Dr. Wily and Dr. Light, save for Shadow Man, who was an existing robot found in the ruins that he helped Wily restore. Shadow Man is hinted and later revealed to have served Ra Moon anciently, as he is the only Robot Master to serve Ra Moon without having to be duped or controlled by its power.
It later appears briefly in the standalone story arc "Rock of Ages", where he evidently turned against Dr. Wily and Wily is begging Mega Man to destroy him. Interestingly, Mega Man reacts as if he had fought and destroyed Ra Moon before, indicating that the story is set some time in the future.
Ra Moon also appeared during the first issue of the Worlds Collide crossover, and sensed the power of the blue Chaos Emerald. It wanted to study it, but was denied the chance by Wily, who later put it to use alongside the resources of Dr. Eggman to create the Wily Egg and Skull Egg Zone. Dr. Light, in the rewritten reality in Sonic the Hedgehog #250, also reminded Wily of Ra Moon's rebellion against him. The same issue also possessed a teaser hinting at the Ra Moon story arc of Issues 28 and 29-32.
It began its revolt against Dr. Wily in Issue 28 and revealed its plans to Wily: It was originally an alien supercomputer, but decided that, because humanity couldn't progress any further with his help, to exterminate it, and later decided to unleash an EMP wave to short out all circuitry and eventually kill off all humans (his motives for this are unknown, although his later death throes implied that he was planning on making Earth into a new home for his offspring, the Stardroids). Ra Moon then sent out an EMP field shutting down all electronic devices except Wily Robot Masters. Two weeks later, thanks to a EMP coating developed by Dr. Light thanks to data from Break Man, Mega Man, Rush, and a few of Light's Robot Masters are sent to the island to stop the supercomputer. The first line of Wily robots attacks them at first, but after it's revealed humans are dying, they call a truce. Wily's second line of robots, due to them being made from scratch instead of data back-ups, are completely prone to being controlled by Ra Moon. Mega Man alongside Break Man and the remaining Robot Masters, attack Ra Moon and his Robot Masters in a fight for the world. The fight then takes a turn as Wily's new weapon Ra Thor is easily taken control of by Ra Moon due to it being made from Ra Moon tech. The battle wages on and Ra Thor is defeated, but Ra Moon manages to take away the immunity from Wily's first line of robots shutting them down, and the few handful of Robot Masters that came with Mega are defeated as well. Ra Moon unleashes the Ra Devil; however due to Ra Moon directly powering it, the supercomputer's defenses are down, thus allowing Mega Man to destroy it with the Double Mega Buster.
Before shutting down Ra Moon sends a message to its children to avenge it. Mega Man, Drs. Light and Cossack, Roll, Pharaoh Man, Plant Man, and Rush later head back to find evidence that Dr. Wily was being forced to serve Ra Moon. Although they believe Ra Moon is still alive, it remains destroyed and they manage to find evidence for Wily. Ra Moon also appears in Issue 42 as part of a flashback of Shadow Man's, revealing it had been sent to Earth just as the Stardroids were to face off against the Star Marshals, with Shadow Man and the other Kuiper Droids barely succeeding, although at the cost of all but the Kuiper Droid who became Shadow Man being destroyed. Indeed, the only thing that saved both Shadow Man and Ra Moon was that Star Marshal Trio chose to betray his comrades during the battle.
Besides its role in the main story, its fight with Mega Man was also spoofed in the Issue 31's Short Circuits, where an attack from Mega Man caused Ra Moon to surrender immediately due to the attack hitting its eye. It also appeared in Wily's fantasy in the Issue 36's, where Wily claimed to have resisted it-wielding a sword reminiscent of Sword Man's-only to be captured, with Ra Moon gloating that it had captured "Earth's champion" and would force him to do its bidding.
|Super Adventure Rockman|
| Mega Man • Beat • Rush • Dr. Light • Roll • Proto Man • Dr. Wily • Ra Moon|
Cut Man • Guts Man • Ice Man • Bomb Man • Fire Man • Elec Man
| Metal Man • Bubble Man • Heat Man • Flash Man • Quick Man • Shadow Man|
Wood Man • Air Man • Crash Man • Snake Man • Needle Man • Gemini Man
Magnet Man • Hard Man • Top Man • Spark Man • Ra Thor • New Yellow Devil
| Metal Blade • Bubble Lead • Atomic Fire • Time Stopper • Quick Boomerang • Shadow Blade|
Leaf Shield • Air Shooter • Crash Bomber • Search Snake • Needle Cannon • Gemini Laser
Magnet Missile • Hard Knuckle • Top Spin • Spark Shock
|Enemies • Energy Tank • Information Card • Item Box • Lanfront Ruins • Proto Shield|