
Blue Eagle is a fictional character appearing in American comic books published by Marvel Comics. The character is not from the main reality where stories are set in the Marvel Universe, but from an alternate universe.(See Sidebar)

Phillip J. Coulson is a fictional character portrayed by Clark Gregg in the Marvel Cinematic Universe. In the Marvel Cinematic Universe (MCU), he is depicted as a high-ranking member of the espionage agency S.H.I.E.L.D., and has appeared in several forms in media, being integrated into the mainstream Marvel Universe. In Marvel Comics, he is depicted as a former S.H.I.E.L.D. agent, later becoming the supervillain servant of the demon Mephisto.

Haywire is a fictional superhero appearing in American comic books published by Marvel Comics.

"Heroes Reborn" is a 2021 comic book storyline published by Marvel Comics, consisting of a central miniseries written by Jason Aaron and illustrated by Ed McGuinness, as well as a number of tie-in books. The storyline explores a Marvel Universe without the Avengers, though it is unrelated to the 1996–97 storyline of the same name. The plot involves a change in the timeline of the Marvel Universe, which results in a continuity in which the Squadron Supreme are Earth's mightiest heroes while the Avengers never came to be. However, the vampire slayer Blade is the only one aware of the change in history and works to uncover the mystery behind it. The crossover overall received mixed reviews with critics.

Hyperion is a fictional character appearing in American comic books published by Marvel Comics, of which there are several notable versions. The original Hyperion made his debut in The Avengers #69, created by writer Roy Thomas and artist Sal Buscema. The alternate versions are each from a different dimension of the Marvel Multiverse, and consist of both heroes and villains. Thomas says that the character was intended as a pastiche of DC's iconic hero Superman.

Nighthawk is the name of several fictional characters appearing in American comic books published by Marvel Comics. There have been six versions of the character: a supervillain-turned-superhero from the mainstream Marvel Universe continuity, Kyle Richmond, who belonged to the team Squadron Sinister; and five from alternate universes, who belonged to various incarnations of the team Squadron Supreme, including Neal Richmond and Jackson "Jack" Norris.

Redstone is the name of two fictional characters appearing in American comic books published by Marvel Comics.

The Skrulls are a fictional race of extraterrestrial shapeshifters appearing in American comic books published by Marvel Comics. The Skrulls first appeared in Fantastic Four #2 and were created by Stan Lee and Jack Kirby. They originated from the planet Skrullos and their empire is located in the Andromeda Galaxy. Their infiltration of Earth was a major event in the Marvel Comics universe as shown in the crossover event, Secret Invasion.

Doctor Spectrum is the name of several fictional characters appearing in American comic books published by Marvel Comics. There have been five versions of the character to date—three supervillains from the mainstream Marvel Universe belonging to the team Squadron Sinister (Earth-616) and two heroes from different alternate universes. The two heroes each belong to a version of the team Squadron Supreme, the Squadron Supreme of Earth-712 and the Squadron Supreme of Earth-31916 respectively). Doctor Spectrum is a pastiche of DC's Green Lantern.

The Squadron Sinister is a fictional supervillain team appearing in American comic books published by Marvel Comics. The Squadron Sinister first appeared in the final panel of The Avengers #69, created by Roy Thomas and Sal Buscema. The team is a pastiche of DC's Justice League.

The Squadron Supreme is a fictional superhero team appearing in American comic books published by Marvel Comics, of which there are several notable alternate versions. The original team was created by Roy Thomas and John Buscema, and derived from the previously created supervillain team Squadron Sinister.

Whizzer is the name of several fictional characters appearing in American comic books published by Marvel Comics. The first character debuted during the Golden Age in USA Comics #1, and was reintroduced in Giant-Size Avengers #1. A second villainous version debuts during the Silver Age in The Avengers #69, and a second heroic version debuting in The Avengers #85.