Superman is the fictional hero in the Superman series of comics.
Superman is my favorite superhero, for several reasons. There are several different characteristics attributed to Superman, some of them from the Superman comic books, but others from alternate universe comic books or comic books about Superman's family, acquaintances, and characters influenced by Superman. The Superman that I am a fan of is the one that fights muggers and is often called a "boy scout," the one that loves Lois Lane and has a geeky alter ego in Clark Kent. This one, represented mainly by the first and second Superman characteristics created, is the one that I believe represents the true definition of a Superhero. The following paragraphs from Wikipedia define the Superman that I am a fan of, the one I think represents Superman the Superhero, and a superhero in general.
In the original Siegel and Shuster stories, Superman's personality is rough and aggressive. The character was seen stepping in to stop wife beaters, profiteers, a lynch mob and gangsters, with rather rough edges and a looser moral code than audiences may be used to today. Later writers have softened the character, and instilled a sense of idealism and moral code of conduct. Although not as cold-blooded as the early Batman, the Superman featured in the comics of the 1930s is unconcerned about the harm his strength may cause, tossing villainous characters in such a manner that fatalities would presumably occur, although these were seldom shown explicitly on the page. This came to an end late in 1940, when new editor Whitney Ellsworth instituted a code of conduct for his characters to follow, banning Superman from ever killing.
Today, Superman adheres to a strict moral code, often attributed to the Midwestern values with which he was raised. His commitment to operating within the law has been an example to many other heroes but has stirred resentment among others, who refer to him as the "big blue boy scout." Superman can be rather rigid in this trait, causing tensions in super hero community, notably with Wonder Woman (one of his closest friends) after she killed Maxwell Lord.
Having lost his homeworld of Krypton, Superman is very protective of Earth, and especially of Clark Kent’s family and friends. This same loss, combined with the pressure of using his powers responsibly, has caused Superman to feel lonely on Earth, despite his many friends, his wife and his parents. Previous encounters with people he thought to be fellow Kryptonians, Power Girl (who is, in fact from the Krypton of the Earth-Two universe) and Mon-El, have led to disappointment. The arrival of Supergirl, who has been confirmed to be not only from Krypton, but also is his cousin, has relieved this loneliness somewhat.
In Superman/Batman #3 (December 2003), Batman observes, "It is a remarkable dichotomy. In many ways, Clark is the most human of us all. Then...he shoots fire from the skies, and it is difficult not to think of him as a god. And how fortunate we all are that it does not occur to him." Later, as Infinite Crisis began, Batman admonished him for identifying with humanity too much and failing to provide the strong leadership that superhumans need.