An ancient alien species that crash landed on Earth millions of years ago, where it was converted into anti-matter. The creature, however, retained the ability to control its ship through telepathy. Over time, the UFO became encased in rock at the bottom of the sea where it lay dormant for countless years.

Near the dawn of the new century, CCI (Crisis Control Intelligence) came across the dormant rock structure and attempted to hoist it out of the water with balloons. The Millennian, however, took control and hosted up the ship out of the water on its own. The rock mass then stayed on the waters' surface, only moving in order to stay adjacent to the sun so it could bath in its light, until it was able to scan a human to try and find the needed genetic materials it would require in order to maintain its form. The humans, though, proved to be of no use, so the rock took to the skies in search of other organisms.

The UFO eventually came across Godzilla who, when scanned, was seen to be the host of the Organizer G1, which the Millennian figured would help aid it in maintaining its normal form. The UFO attacked and defeated Godzilla, but only to crash into the water nearby. Responding to the appearance of the UFO, Japan's Self Defense Force went into action in an attempt to restrain the UFO by roping it with steel cables. Their attempt was in vein, however, as the UFO quickly freed itself at dawn.

The alien craft then proceeded to head for Tokyo, were it rested atop a building. The Millennian then attempted to assimilate all the data in the metropolitan city with invisible tendrils, which wove their way into the building. Come nightfall, the SDF again attempted to deal with the UFO, this time planting mines at the top of the building where the craft rested. The mines failed to deal with the Millennian, though, as the creature's craft was unscathed from the explosion. In retaliation, the extra-terrestrial being destroyed the remainder of the building. Shortly afterwards, the UFO was greeted by Godzilla, the creature whom contained the genetic make up the Millennian needed. The UFO viciously attacked Godzilla, and was able to subdue the monster long enough to extract the needed genetic code, after crushing Godzilla with a building.

After obtaining the Organizer G1, the Millennian slowly emerged from its ship in a ball like form, which quickly changed to resemble its true form. Unfortunately, the Millennian failed to anticipate the horrific side-effects of the radiation spawned cells, as the creature begun to mutate uncontrollably before collapsing to the ground in a hulking mass.

The final result of the Organizer G1 on the Millennian, Orga was mammoth creature compared to the slender appearance of the original alien. Equipped with giant claws and a large protruding back, the monster had mutated into a state that was even larger than Godzilla. Despite its menacing appearance, though, the King of the Monsters quickly rushed in and attacked the hulking monster. Orga seemed confused at these turn of events, either due to shock from its own transformation or a general degrading of its intelligence, as the nuclear saurian was able to land several blows before its alien opponent finally grasped the situation. Once up to speed, the creature fought back ferociously, attempting to fend off the onslaught from Godzilla. Orga called on its nearly destroyed ship to aid it in battle, but the King of the Monsters made quick work of it with another blast of his atomic ray. With the UFO decimated, Godzilla continued to strike the alien being, but the damage inflicted was quickly overcome by the creature's healing factor. A trait that was given to the beast thanks to the properties inherit in its rival's genetic material.

When it looked like Godzilla was running out of options, Orga shifted its strategy as it completely opened its mouth. With its jaws stretched to a drastic degree, the monster then begun to withdraw its own stomach in order to consume its foe. Godzilla seized the opportunity and charged head first into Orga's mouth. The brutish alien then slowly started to consume the creature. As Godzilla slipped further into the beast’s stomach, Orga continued to mutate. Its color slowly started to change green while rows of jagged dorsal fins emerged from its back. The creature managed to grow a staggering height of 70 meters before Godzilla finally unleashed his Inner-Radiation while inside Orga's mouth. Unable to react in time, Orga was helpless in his current situation as the powerful blast disintegrated the monster's upper half, killing the former Millennian.