* Wolverine has shown a willingness to kill and anti-social behavior. He belongs to an underclass of morally ambivalent anti-heroes who are coarser and more violent rather than classic superheroes. Others include Green Arrow, Black Canary, Blade and, in some incarnations, Batman. Namor the Sub-Mariner is the earliest example of this archetype, originally appearing in 1939. Some, such as Wolverine and Daredevil, are often repentant about their actions, while others, such as The Punisher and Rorschach, are unapologetic.
* Some superheroes have been created and employed by national governments to serve their interests and defend the nation. Captain America was outfitted by and worked for the United States Army during World War II and Alpha Flight is a superhero team formed and usually managed by an arm of the Canadian Department of National Defence. The Ultimates, in particular, work directly under the U.S. government and are used as a metaphor for U.S. military and political power. The Savage Dragon is virtually unique in that he began his superhero career as police officer, rather than a costumed vigilante. Wonder Woman's day job also works for the government as an agent.
* Many superheroes have never had a secret identity, such as Luke Cage or the members of The Fantastic Four. Others who once had secret identities, such as Captain America and Steel, later made their identities public. The third Flash is a rare example of a "public" superhero who regained his secret identity.
* The Hulk is usually defined as a superhero, but he has a Jekyll/Hyde relationship with his alter ego. When enraged, scientist Bruce Banner becomes the super-strong Hulk, a creature of little intelligence and self-control. His actions have often either inadvertently or deliberately caused great destruction. As a result, he has been hunted by the military and other superheroes.
* While most superheroes traditionally gained their abilities through accidents of science, magical means or rigorous training, the X-Men and related characters are genetic mutants whose abilities naturally manifest at puberty. Mutants more often have difficulty controlling their powers than other superheroes and are persecuted as a group.
* Some superhero identities have been used by more than one person. A character (often a close associate or family member) takes on another's name and mission after the original dies, retires or takes on a new identity. The Flash, Blue Beetle and Robin are notable mantles that have passed from one character to another. Green Lantern and Nova are standard titles for the thousands of members of their respective intergalactic "police corps". The Phantom and the Black Panther both adopted personae and missions that have lasted several generations.
* Thor and Hercules are mythological gods reinterpreted as superheroes. Wonder Woman, while not a goddess in her current incarnation, is a member of the Amazon tribe of Greek mythology given many "god like" powers, enough to challenge the gods themselves.
* Spawn, Etrigan, Ghost Rider and Hellboy are actual demons who have been manipulated by circumstance into being forces of good.
* Superman, the Silver Surfer, Martian Manhunter, and Captain Marvel (the Marvel Comics character) are extraterrestrials who have, either permanently or provisionally, taken it upon themselves to protect the planet Earth.
* Adam Strange, on the other hand, is a human being who protects the planet Rann.
* Some characters tread the line between superhero and villain because of a permanent or temporary change in character or because of a complex, individualistic moral code. These include Juggernaut, Emma Frost, Catwoman, Elektra and Venom. This change often coincides with a spin-off series in which the character must be a likable protagonist.
* Because the superhero is such an outlandish and recognizable character type, several comedic heroes have been introduced, including The Tick, The Flaming Carrot, The Great Lakes Avengers, Herbie Popnecker, The Powerpuff Girls and The Simpsons’ Radioactive Man. Early, Harvey Kurtzman-edited issues of Mad Magazine featured several parodies of superheroes and count as some of the first satiric treatments of this subject matter.
The first known female superhero is writer-artist Fletcher Hanks's minor character Fantomah, an ageless, ancient Egyptian woman in the modern day who could transform into a skull-faced creature with superpowers to fight evil; she debuted in Fiction House's Jungle Comics #2 (Feb. 1940), credited to the pseudonymous "Barclay Flagg".
Another seminal superheroine is Invisible Scarlet O'Neil, a non-costumed character who fought crime and wartime saboteurs using the superpower of invisibility; she debuted in the eponymous syndicated newspaper comic strip by Russell Stamm on June 3, 1940. A superpowered female antihero, the Black Widow — a costumed emissary of Satan who killed evildoers in order to send them to Hell — debuted in Mystic Comics #4 (Aug. 1940), from Timely Comics, the 1940s predecessor of Marvel Comics.
Though non-superpowered, like the Phantom and Batman, the earliest female costumed crimefighters are The Woman in Red, introduced in Standard Comics' Thrilling Comics #2 (March 1940); Lady Luck, debuting in the Sunday-newspaper comic-book insert The Spirit Section June 2, 1940; Miss Fury, debuting in the eponymous comic strip by female cartoonist Tarpé Mills on April 6, 1941; the Phantom Lady, introduced in Quality Comics Police Comics #1 (Aug. 1941); and the Black Cat, introduced in Harvey Comics' Pocket Comics #1 (also Aug. 1941). The superpowered Nelvana of the Northern Lights debuted in Canadian publisher Hillborough Studio's Triumph-Adventure Comics #1 (Aug. 1941).
The first widely recognizable female superhero is Wonder Woman, from All-American Publications, one of three companies that would merge to form DC Comics. She was created by psychologist William Moulton Marston with help and inspiration from his wife Elizabeth and their companion Olive Byrne Wonder Woman debuted in All Star Comics #8 (Jan. 1942).
Starting in the late 1950s, DC introduced Hawkgirl, Supergirl, Batwoman and later Batgirl, all female versions of prominent male superheroes. Batgirl would eventually shed her "bat" persona and become Oracle, the premiere information broker of the DC superhero community and leader of the superheroine team Birds of Prey In addition, the company introduced Zatanna and a second Black Canary and had several female supporting characters that were successful professionals, such as the Atom's love-interest, attorney Jean Loring.
As with DC's superhero team the Justice League of America, with included Wonder Woman, the Marvel Comics teams of the early 1960s usually included at least one female, such as the Fantastic Four's Invisible Girl, the X-Men's Marvel Girl and the Avengers' Wasp and later Scarlet Witch. In the wake of second-wave feminism, the Invisible Girl became the more confident and assertive Invisible Woman, and Marvel Girl became the hugely powerful destructive force called Phoenix.
In subsequent decades, Elektra, Catwoman, Witchblade, and Spider-Girl became stars of popular series. The series Uncanny X-Men and its related superhero-team titles included many females in vital roles.
The idealized physiques and frequently sexual costumes (such as those of Power Girl, Emma Frost and Starfire) of female superheroes have led to accusations of sexism.
In 1992, Marvel revealed that Northstar, a member of Alpha Flight, was homosexual, after years of implication. This ended a long-standing editorial mandate that there would be no LGBT characters in Marvel comics. Although some secondary characters in DC Comics' mature-audience miniseries Watchmen were gay, Northstar was the first openly gay superhero. Other gay and bisexual superheroes have since emerged, such as Gen¹³'s Rainmaker, and The Authority's gay couple Apollo and Midnighter.
In the mid-2000s, some characters were revealed gay in two Marvel titles: The Ultimate Marvel incarnation of the X-Men’s Colossus and Wiccan and Hulkling of the superhero group Young Avengers. In 2006, DC revealed in its Manhunter title that longtime character Obsidian was gay, and a new incarnation of Batwoman was introduced as a "lipstick lesbian" to some media attention.
* Superheroes who maintain a secret identity often wear a mask, ranging from the domino masks of Green Lantern and Ms. Marvel to the full-face masks of Spider-Man and Black Panther. Most common are masks covering the upper face, leaving the mouth and jaw exposed. This allows for both a believable disguise and recognizable facial expressions. A notable exception is Clark Kent, who wears nothing on his face while fighting crime as Superman, but uses large glasses in his civilian life.
* A symbol, such as a stylized letter or visual icon, usually on the chest. Examples include the uppercase "S" of Superman, the bat emblem of Batman, and the spider emblem of Spider-Man. Often, they also wear a common symbol referring to their group or league, such as the "4" on the Fantastic Four's suits, or the "X" on the X-Men's costumes.
* Form-fitting clothing, often referred to as tights or Spandex, although the exact material is usually unidentified. Such material displays a character’s athletic build and heroic sex appeal and allows a simple design for illustrators to reproduce.
* While a vast majority of superheroes do not wear capes, the garment is still closely associated with them, likely due to the fact that two of the most widely-recognized, Batman and Superman, wear capes. In fact, police officers in Batman’s home of Gotham City have used the word "cape" as a shorthand for all superheroes and costumed crimefighters. Other shorthands for superheroes are used in the computer game City of Heroes, when a player's hero fights with some of the game's supervillain groups such as the Hellions, Skulls, and Clockwork, the villains will often say, "The capes are trying to stop us," "I smell spandex" (referring to the spandex costumes some heroes wear), or "Attack the mask" (an allusion to the masks used by some superheroes). The comic book series Watchmen and the animated movie The Incredibles humorously commented on the potentially-lethal impracticality of capes. In Marvel Comics the term "cape-killer" has been used to describe anti-superhuman conventional forces.
* While most superhero costumes merely hide the hero’s identity and present a recognizable image, parts of some costumes have functional uses. Batman's utility belt and Spawn’s "necroplasmic armor" have both been of great assistance to the heroes. Iron Man's armor, in particular, protects him and provides technological advantages.
* When thematically appropriate, some superheroes dress like people from various professions or subcultures. Zatanna, who possesses wizard-like powers, dresses like a magician, and Ghost Rider, who rides a superpowered motorcycle, dresses in the leather garb of a biker.
* Several heroes of the 1990s, including Cable and many Image Comics characters, rejected the traditional superhero outfit for costumes that appeared more practical and militaristic. Shoulder pads, kevlar-like vests, metal-plated armor, knee and elbow pads, heavy-duty belts, and ammunition pouches were common features. Other characters, such as The Punisher or The Question, opt for a "civilian" costume (mostly a trench coat).