The Microverse is only accessible by the energies released when shrinking beyond the sub-atomic level.
The Sword in the Star is credited for creating the Microverse.
Points of Interest
The central world within the Microverse is Homeworld, a series of linked planetoids orbiting twin Suns. Homeworld became the site of Wayfinder's tomb, as well as the main transfer point to Earth.
Neighboring Homeworld are the crimson planet Kaliklak, rich in vegetation and home of the humanoid Insectivorids, and Spartak, a rocky lifeless planet which sacrificed its "worldmind" – the planet's soul – to stop a savage despot. Homeworld, Kaliklak, and Spartak are all planets in a cluster of solar systems which form a galactic-size DNA shape called the Spiral Path.
Surrounding the Spiral Path is the Spacewall, a near-impregnable barrier separating it from other dimensions as well as the rest of the Microverse. However, various methods have been used to cross the Spacewall in recent times.
Other locations exist in the Microverse which was formerly part of separate Microverses. The Planet K'ai is inhabited by massive beasts and green-skinned humanoids. There are also several known planets of Sub-Atomica, including Mirwood, Tok, and Traan, home of its former oppressive ruler, Psycho-Man.
Fantastic Four Annual #5 (1967)
The origin of the Microverse actually begins over 15,000 years from now in an alternate future when humanity's "homeworld." Earth, becomes uninhabitable and the human race spread across the galaxy. Some new civilizations prospered, like the Ithacons, while others descended into barbaric ways, like the insane conquerors, the Haaman.
Years of war between the two factions finally ended when Prince Wayfinder of the Ithacons obtained the legendary Sword in the Star and defeated the Haaman. Survivors of the war became the wanderers, homeless refugees once more. Prince Wayfinder used the Sword in the Star to take them 65 million years into the past to settle Earth in prehistory, but found that they did not belong there either.
A people out of time, a paradoxical civilization of future and past, the Sword offered them a new universe, accessed by the energies released when shrinking beyond the sub-atomic level, this action created the Microverse, fulfilling the last part of its destiny. The Sword in the Star brought the wanderers into the Microverse and bound its energy there. Known only as the Enigma Force, it is the foundation of the Microverse, and the power that finally gave the Wayfinder's people a home.
Earth’s first encounter with this real was a one man invasion by Psycho-Man, chief scientist of Sub-Atomica. The dangerous villain was eventually defeated by the combined forces of the Fantastic Four, the Inhumans, and the Black Panther, but this would not be the last spectacular battle fought between the two worlds. The Microverse has a rich history of its own and many heroes that write it.
Over 1,000 years ago, Homeworld was a thriving civilization full of wondrous technology and robotics. The beloved Regents of the capital city Lord Dallan Rann and his wife Lady Sepsis, had a son Arcturus Rann who agreed to partake in a millennial journey across the Microverse. In his mission, Rann encountered manifestations of the Enigma Force and became intrinsically linked with it.
Returning from his journey, Rann was immediately attacked by a regime that had slain the existing monarchs. Rann quickly joined the underground rebellion, which included the bold Princess Mari, the charmingly affable Insectivorid thief Bug, and the stoic king of Spartak , Rann led his team to liberate Homeworld through the power of the Enigma Force.
Commander Rann and his team became well-known freedom fighters and shared several adventures on Earth. They battled beside mighty heroes like the Fantastic Four, the X-Men, and the Avengers. The mad Titan, Thanos, took interest in the Microverse and battled against homeworld's heroes and the X-Men. Though the heroes triumphed, the Microverse and other subatomic universes merged into a single universe in the aftermath. The heroes kept a low profile for a time, but eventually found new adventures. They teamed up with the mutant time-traveler Cable to rescue his ally, Kane, from the manipulative resident of the Microverse, Psycho-Man. Canadian super-heroes Alpha Flight ventured to Homeworld and aided Rann and Mari against a new rising despot. The team also helped Captain Marvel locate his ally Drax, who was drawn into a scam on the planet of K'ai by Visalia, a woman falsely claiming to be the sister of Queen Jarella, while Drax was mistaken for the Hulk.
The ever flirtatious Bug eventually passed through the Spacewall, and he was imprisoned by the Kree for an unidentified crime. He was forced to join Star-Lord and his team to defeat the techno-organic Phalanx on the Kree's home planet, of Hala. Bug remained with Star-Lord afterward as part of his Guardians of the Galaxy, where Bug witnessed the rebirth of Thanos, threatening the fate of the entire universe.