Captain Universe is the identity which has been assumed by each of the hundreds of beings who have been empowered by the Uni-Power, a mysterious energy source originating from the extraterrestrial dimension known as the Microverse. The creation of the Microverse was engineered by the Makers, giant beings resembling Celestials, though the details of their involvement are uncertain.

A million years ago, a time traveler named Prince Wayfinder defended Earth from an invasion by evil Whirldemons. Using the cosmic power of the enigmatic Sword in the Star, Wayfinder opened an one-dimensional/temporal portal, created the Microverse to provide a new home for his people and bound the demons, preventing their entry into the Microverse. The Sword in the Star bonded with Prince Wayfinder, transforming itself into the Enigma Force with Wayfinder as its guardian. In times of distress, the Enigma Force manifests the Uni-Power, which selects a host, surrounding them with a field of energy which transforms them into the costumed Captain Universe, and imparts to them some of the knowledge they will need to yield their powers. The Uni-Power occasionally communicates with the host personally in cases where the host needs guidance, or when the Uni-Power has a specific agenda.

The first known human to yield the Uni-Power was Gilbert Wiles, who became Captain Universe to help stop a plane hijacking. When the crises was over, Wiles lost the power, but was so overwhelmed by the experience that he devoted himself to studying the Uni-Power, hoping to regain it. The next known host was astronaut Ray Coffin, who had entered the Microverse through the Prometheus Pit, a portal on Earth leading to that dimension. The Time Traveler requested Coffin’s aid against the evil Baron, a Microverse tyrant who sought to conquer both dimensions, and bestowed the Captain Universe power upon him. Coffin drove the Baron from Earth, and the Prometheus Pit was sealed. Coffin then lost his powers.

When Mister E, a native of the Shadow Realm, attempted to turn Earth’s sun into a black star, the Uni-Power manifested itself in Coffin again to face the threat, but the strain on Coffin caused a heart attack. The Uni-Power chose his teenage son Steve Coffin instead, and Steve defeated Mister E. The Uni-Power later empowered twin siblings, homemaker Ann Stanford and private detective Clare Dodgson, who shared the Captain Universe powers to defeat the crime-lord Nemesis, revealed to be Ann’s own husband. The Uni-Power entered cat burglar Monty Walsh, who had been shot by agents of the gangster Guido Carboni. Walsh succeeded in bringing down Carboni and hoped to use the Captain Universe powers to become a crime boss, but when the Uni-Power left him, he apparently died from his gunshot wounds.

When the Microverse was imperiled by a merging with Earth-616’s dimension caused by the reawakened Whirldemons, Wayfinders descendent Arcturus Rann and Earth’s sorcerer supreme Dr. Strange found Wayfinder’s tomb, and the Sword in the Star empowered them both to become a merged Captain Universe. They used the Uni-Power to halt Earth’s merging with the Microverse, and were restored to their own bodies when the crises ended. When a crazed military officer named Jamie Custer attempted to launch a nuclear missile, the Uni-Power transformed Bruce Banner (Hulk) into Captain Universe. Banner’s other self, the Hulk, manifested itself as a separate entity, and its natural enmity to Banner led to a struggle between the two, but Banner finally destroyed the missile and neutralized the fallout. When the Uni-Power left Banner, he and Hulk remerged with each other.

An unidentified female Captain Universe was among the heroes of Earth assembled by the Grandmaster to serve as potential participants in his game against Death, but she was not selected. Later, young student Delayne Masters became Captain Universe to save his teacher from a schoolyard bully named Willie Johnson. Although the Uni-Power left Delayne before he had beaten Willie, Delayne had gained enough confidence from the experience that he was able to defeat Willie on his own. The Uni-Power once transformed physics professor Evan Swann into Captain Universe to halt the Quantum Mechanic, an extraterrestrial who believed that the law of probability was a flaw in reality that should be corrected by breaking the Earth down into subatomic particles, Swann destroyed the Quantum Mechanic to save the Earth.

The Uni-Power’s next known recipient was Peter Parker, secretly Spider-Man. When the Uni-Power first possessed Parker, he was struck by electricity in a laboratory accident while working with professor Max Lubisch. The accident blocked some of the Uni-Power’s energy from reaching Parker and he mistakenly believed that his increased powers were a result of the accident. Spider-Man found himself facing increased threats from super-villains due to Loki’s so called “Acts of Vengeance!” conspiracy, in which the villain community traded opponents, and he found he needed his new powers to face the Trapster, Titania, Magneto, the Brothers Grimm, Goliath, the Hulk, the Rhino, Shocker, Hydro-Man, TESS-One, Dragon Man, Terminus and Graviton. When Loki’s plot was foiled by Earth’s heroes, he attempted new mischief by merging three Sentinels into the Tri-Sentinel. This proved to be the threat the Uni-Power had chosen Spider-Man for, and he gained full access to the Uni-Power. With the Tri-Sentinels defeat, the Uni-Power departed, and Parker found himself wiser for the experience, having remained true to himself even with the cosmic powers of Captain Universe. Peter’s tenure as Captain Universe led to further troubles when nearly all of his foes from “Acts of Vengeance” returned for rematches; he was also kidnapped along with other former Captain Universe hosts by the Psycho-Man, a tyrant of the Microverse who was after the Uni-Power, but Spider-Man and his fellow prisoners escaped and defeated him.

Another Captain Universe was a toddler named Eddie Price, chosen to end the threat of the demons Gart and Rath. Later, time-traveling members of the Guardians of the Galaxy visited the modern era, and they attempted an attack upon the Badoon, hoping to prevent the Badoon invasion of their own timeline. To prevent this, the Uni-Power transformed a Badoon named L’Matto into Captain Universe to defeat the Guardians. The Guardians’ absent leader Major Victory came to aid them alongside Dr. Strange, and Dr. Strange forced the Uni-Power to depart L’Matto so that the Guardians could escape back to their own time.

The Uni-Power’s next known host was the paralyzed Elijah Jackson. When he became Captain Universe to save his daughter from attackers, his paralysis was temporarily healed and he had a chance to express his love for his daughter before the Uni-Power departed, restoring him to his paralyzed condition. Though accounts vary, perhaps due to reality distortion, a University of Tennessee veterinary student became Captain Universe to aid the X-Men against the mutant Roger Fieldston, who was using his power to mutate others. Captain Universe used the Uni-Power to reverse Fieldston’s powers so that he could heal everyone he affected in his rampage.

An unusual Captain Universe was Roland Taylor, a schizophrenic writer. The Uni-Power healed his mind, but he found himself pursued by Division U, a scientific team trying to analyze the Uni-Power, whose ranks included Steve Coffin, angered to find another person with his one-time powers. The Uni-Power was also pursued by the Enigma Hunters, extraterrestrials from the Microverse who sought its powers for themselves. When the Uni-Power tried to leave Taylor, his schizophrenic side reasserted itself, forcing the Uni-Power to remain. The Uni-Power eventually departed from Taylor through unrevealed circumstances.

The Uni-Power went on to possess police officer Ted Simmons, but it began to suffer inexplicable power fluctuations. While Simmons was battling gunmen, the Uni-Power briefly deserted him, and one of Simmons’ fellow officers was shot dead as a result. The Uni-Power could not understand what had happened to it, and began to search for answers. Needing more power, it also began to seek individuals who were already superhuman so that it could duplicate their powers.

It first returned to Bruce Banner, this time possessing him and the Hulk as a single entity. They sought out Gilbert Wiles, who was still researching the Uni-Power, and he attempted to assist it, but agents of A.I.M. made an attempt on the Uni-Power, and while the empowered Hulk fought them, an invisible A.I.M. agent killed Wiles’ business partner, David Garrett. To help clear Gilbert’s name, the Uni-Power joined with Matthew Murdock, alias Daredevil, who had taken Wiles as his client. Bonding with the Uni-Power enhanced Daredevil’s superhuman senses to such a degree that he could barely function, but he also regained his eyesight as a result. Murdock proved Wiles’ innocence in court, and suggested that the Uni-Power attempt to study A.I.M.’s findings on its situation, hoping it might shed light on the power fluctuations.

To invade an A.I.M. base, the Uni-Power joined with the mutant X-23 (Laura Kinney), who was sympathetic to the Uni-Power’s plight, having been a victim of experimentation herself. They were also assisted by the S.H.I.E.L.D. agent Scorpion (Carmilla Black), and destroyed all of A.I.M.’s intelligence on the Uni-Power in the hopes that they would cease pursuing it. The Uni-Power sought aid from Fantastic Four leader Mr. Fantastic, but the Four were attacked by Gladiator (Kallark) of the Shi’ar Imperial Guard, who believed that the Uni-Power’s fluctuations made it a threat to the universe. The Uni-Power possessed the Invisible Woman to hold off Gladiator, and finally joined with Gladiator briefly so that he could see its recent fluctuations were uncontrolled. Gladiator offered to bring the Uni-Power back to the Shi’ar with him to seek answers.

As they traveled to the Shi’are empire, Gladiator and the Uni-Power were captured by Krosakis, an extraterrestrial who fed upon cosmic energies, and he forced the Uni-Power to bond with him so that he could have its power. The Silver Surfer (Norrin Radd) sensed the Uni-Power’s distress and came to its aid. In battle with Krosakis, the Surfer was able to drive the Uni-Power from his body. The Uni-Power then bonded with the Surfer, and he was able to use his Power Cosmic to halt the fluctuations temporarily. After freeing Gladiator and Krosakis’ other slaves, the Surfer brought the Uni-Power to Gabriel Vargas, a soldier who had been crippled while on a tour of duty. The Uni-Power chose Vargas as its new host while it continued to investigate its power fluctuations.