The Entropy Cloud is far more than mere entropy bulldozing a universe. It is a rift in the very fabric in the space/time of Microspace bending past, present, and future together. This would be bad enough on its own were it not for the fact that the cloud itself seems sentient to a degree reaching out to consume planets.
It has also been referred to as the Entropy Storm or (incorrectly) as a Chaos Storm. Which to be fair are much cooler names.
The Entropy Cloud came about when the Time Travelers attempted to enerchange with time itself. All things within the cloud were held in a quantum state, both existing and not at the same time. At the heart of the cloud rested a maddened Time Traveler.
The cloud's destructive rampage through space caused the already quite large divide between the Ministry of Science and the Ministry of War to descend into full scale civil war. As a result of the cloud, many citizens believed the end of all things had come and began taking bets on which worlds would die first. Despite the war, the Ministry of Science sent a squad of Biotrons to Saqqura to observe the world being destroyed by the cloud. The squad noticed that the cloud's tendrils were reaching out for Saqqura with signs of intelligence. Though the scientists understandably wanted to evacuate, the Biotrons insisted on staying to be destroyed with the planet so their final moments could be recorded and sent to the Ministry for further analysis.
The cloud would occasionally eject debris. When Baron Karza was brought his own helmet, though heavily weathered with age, he began to speculate that the cloud was in fact a rift in time.
The cloud however bent time and Karza arrived inside years before his quarry. Micronus Prime at the very heart of the cloud, who he soon determined was the creator of Microspace. Learning that his creator came from a different universe, Karza studied the Prime's personal Space bridge and through it was able to make contact with the other reality and discover Ore-13 which halted the cloud's effects. The Micronauts (only a few days having passed from their perspective) reunited with Karza when they tracked down the energy emanations from Micronus's spark.The Baron took this opportunity to study the cloud and discovered the inert body of
Though Karza had made an attempt to use Dire Wraith magic to bring the Ore-13 into Microspace, he was ultimately defeated and forced back to his realm. He stewed for a year as he watched the cloud devour more of Microspace until Shazraella convinced him to abandon Microspace to the cloud and start anew on Earth. While on Earth, Karza revealed to her the nature of the cloud and how it could not be destroyed without negating Microspace's existence. After Oziron Rael had ascended to become a Time Traveler, he and his new brothers tore the Mad Time Traveler from Shazraella before pledging to Optimus Prime that they would repair all the damage the Entropy Cloud had caused.
In the timeline from which the Sentient Time Chamber hailed from, the Entropy Cloud consumed everything in Microspace, the last system being Udunax. The Chamber used his powers to shield himself and a handful of Kronus from total event collapse before they drifted within the Entropy Cloud for thousands of years.
- Entropy Cloud at the TFWiki