Captain Universe is the generic name for the recipient of the Uni-Power, a special kind of energy that endows an individual with a host of superhuman powers. The Uni-Power is a manifestation of the Enigma Force, an extradimensional energy originating in the subatomic realm called the Microverse, wielded by the ethereal Time Travelers. The Uni-Power appears to be a floating globule of luminescent energy that appears seemingly from out of nowhere to engulf an individual, conferring upon him or her the costume, powers and knowledge of Captain Universe. The Uni-Power only manifests itself at a time of crisis - be it personal or worldwide - and withdraws when the crisis has abated. How it chooses the individual who get full possession of the Uni-Power to solve his or her crisis is yet known. The Uni-Power does not remain unmanifested for very long. It transfers from one person to another across the face of the world with no perceptible time lapsing between. At all times somewhere on Earth there is a Captain Universe (once, a pair of twins were Captains Universe simultaneously).

The Uni-Power can be manipulated by each Captain Universe in a variety of ways, dependent upon each recipient's imagination and strength. The Uni-Power amplifies strength about fifty times Thus if a person can normally lift (press) 150 pounds, he or she would now be able to lift approximately 7,500 pounds. Each Captain Universe is also granted the ability to fly by harnessing the Uni-Power's energy to generate antigravitions. The Uni-Power also grants the ability to manipulate structure of objects, changing one shape into another, or even transmuting the elements of an object from one substance to another. This power of molecular manipulation extends to both organic and inorganic matter. Thus the Uni-Power can be used to heal wounds by rearranging the molecules of flesh, tissues or organs, or it can be used to alter the physical characteristics of a person (enlarging the hands of changing their features). The Uni-Power can also be wielded like an energy-beam, generating a luminous burst of energy with a concussive force determined to an extent by the user's ability. The Uni-Power also grants each Captain Universe Uni-Vision which enable the user to see the molecular structure of an object, to see through walls, or to see long distances away. The Uni-Vision is emitted by Captain Universe's eyes and produces a visible beam of energy. This energy has certain hypnotic-side-effects: a skillful wielder of the Uni-Vision can use it to hypnotize people into telling the truth.

So far, the identities and exploits of but a handful of Captain Universes have been disclosed. The first was ex-astronaut Ray Coffin (MICRONAUTS #8) who wielded the Uni-Power to help battle the Microversian tyrant Baron Karza. Other recipients have been Steve Coffin, the son of the original Captain Universe (MARVEL SPOTLIGHT #9), the twins Clare and Ann Dodgson (MARVEL SPOTLIGHT #10), the cat burglar Monty Walsh (MARVEL SPOTLIGHT #11), the Hulk's alter ego Bruce Banner (HULK ANNUAL #10) and the sorcerer supreme Doctor Strange (MICRONAUTS #35).