I'm really not very clued up on super heroes, nor do i know anything about comic book culture, but i'll chip in anyway in case whatever i say happens to be relevant.
A hero is someone who places the needs of others above the needs of themselves. A hero is someone who is able to stare in the face of death without turning away. A hero is an ordinary man or woman who does extraordinary things. These things are acts of courage, bravery and self-sacrifice. Heroism may run the gambit from physical to intellectual. Dr. King was a hero of civil rights, and his battle was fought with words. Firemen, doctors and policemen are heroes who save lives.
However, heroism is not entirely contained within such impacting circumstances. If someone is feeling suicidal, and their closest friend is able to lift them out of that pit of depression even for a little while, they are also a hero, whether they are recognised for it or not. A hero is someone to be admired, to be emulated and to be acknowledged, both within others and within ourselves.