The origin story of Superman relates that he was born Kal-El on the planet Krypton, before being rocketed to Earth as an infant by his scientist father Jor-El, moments before Krypton's destruction. Discovered and adopted by a Kansas farmer and his wife, the child is raised as Clark Kent and imbued with a strong moral compass. Very early he started to display superhuman abilities, which upon reaching maturity he resolved to use for the benefit of humanity.

The four core individuals traditionally associated with the Fantastic Four, who gained superpowers after exposure to cosmic rays during a scientific mission to outer space, are: Mr. Fantastic (Reed Richards), a scientific genius and the leader of the group, who can stretch his body into incredible lengths and shapes; the Invisible Woman (Susan "Sue" Storm), Reed's wife, who can render herself invisible and project powerful force fields; the Human Torch (Johnny Storm), Sue's younger brother, who can generate flames, surround himself with them and fly; and the monstrous Thing (Ben Grimm), their grumpy but benevolent friend, who possesses superhuman strength and endurance. Since the original four's 1961 introduction, the Fantastic Four have been portrayed as a somewhat dysfunctional yet loving family. Breaking convention with other comic-book archetypes of the time, they would squabble and hold grudges both deep and petty, and eschew anonymity or secret identities in favor of celebrity status.

The Hulk is cast as an emotional and impulsive alter ego of the withdrawn and reserved physicist Dr. Bruce Banner. The Hulk appears shortly after Banner was accidentally exposed to the blast of a test detonation of a gamma bomb he invented. Subsequently, Banner will often involuntarily transform into the Hulk, depicted as a giant, raging monster, leading to extreme complications in Banner's life. In Hulk: The Incredible Guide, Stan Lee revealed that the Hulk was a combination of Dr. Jekyll and Mr. Hyde, and Frankenstein.

Batman's secret identity is Bruce Wayne, a wealthy industrialist, playboy, and philanthropist. Witnessing the murder of his parents as a child, Wayne trains himself both physically and intellectually and dons a bat-themed costume in order to fight crime.Batman operates in the fictional American Gotham City, assisted by various supporting characters including his sidekick Robin and his butler Alfred Pennyworth, and fights an assortment of villains influenced by the characters' roots in film and pulp magazines. Unlike most superheroes, he does not possess any superpowers: he makes use of intellect, detective skills, science and technology, wealth, physical prowess, and intimidation in his war on crime.