The Marvel era began in 1961, the year that the company launched The Fantastic Four and other superhero titles created by Stan Lee, Jack Kirby, Steve Ditko and many others. The Marvel brand, which had been used over the years, was solidified as the company's primary brand.

Marvel counts among its characters such well-known superheroes as Spider-Man, Iron Man, Captain America, the Hulk, Thor, Wolverine, Ant-Man, the Wasp, Black Widow, Captain Marvel, Black Panther, Squirrel Girl, Doctor Strange, the Scarlet Witch, She-Hulk, the Vision, Psylocke, Ghost-Spider, the Falcon, the Winter Soldier, Ghost Rider, Blade, Daredevil, Ms. Marvel, the Punisher and Deadpool. Superhero teams exist such as the Avengers, the X-Men, the Fantastic Four and the Guardians of the Galaxy as well as supervillains including Doctor Doom, Magneto, Thanos, Loki, Green Goblin, Kingpin, Red Skull, Ultron, the Mandarin, MODOK, Doctor Octopus, Kang, Dormammu, Venom and Galactus. Most of Marvel's fictional characters operate in a single reality known as the Marvel Universe, with most locations mirroring real-life places; many major characters are based in New York City. Additionally, Marvel has published several licensed properties from other companies. This includes Star Wars comics twice from 1977 to 1986 and again since 2015.

DC Comics is one of the largest and oldest American comic book companies. The majority of its publications take place within the fictional DC Universe and feature numerous culturally iconic heroic characters, such as Superman, Batman, Wonder Woman, Green Lantern, Flash, Aquaman, Martian Manhunter, Cyborg, Green Arrow, Starfire, Shazam, Supergirl, Batwoman, Batgirl, Robin, Nightwing, Black Canary, Hawkman, Hawkgirl, Huntress, Static, Zatanna and Bumblebee.

It is widely known for some of the most famous and recognizable teams including the Justice League, the Justice Society of America, the Green Lantern Corps, the Young Justice, the Suicide Squad, the Birds of Prey, the Gotham City Sirens, the Teen Titans, and the Legion of Super-Heroes.

The universe also features a large number of well-known supervillains who oppose the superheroes such as Lex Luthor, Joker, Darkseid, Harley Quinn, General Zod, Catwoman, Brainiac, Scarecrow, Veronica Cale, Poison Ivy, Metallo, Black Manta, Black Mask, Doomsday, Ares, Bizarro, Bane, Cheetah, Mr. Freeze, Doctor Poison, Penguin, Circe, Sinestro, Riddler, Star Sapphire, Two-Face, Reverse-Flash, King Shark, Ra's al Ghul, Giganta, Gorilla Grodd, and Black Adam. The company has published non-DC Universe-related material, including Watchmen, V for Vendetta, Fables and many titles under their alternative imprint Vertigo.