| A secret identity is the alternate identity in which the hero in
hero fiction can live the semblance of a normal life. It is one
of the most closely guarded secret of mystery men and others for
fear of retribution against those he or she cares about should his
identity become known.
The best known example of a secret identity is Superman's alternate
ego Clark Kent. This is a prime example of how the hero keeps
his secret identity to allow him to live a seemingly normal life.
Superman is known to the general public to be from another planet
and is held in nearly god-like status by normal humans. For him to
have a normal social life without an alternate identity would be
nearly impossible, but as Clark Kent, Superman is able to hold down
a job and have friendships and even romances. The other issue is one
of safety. For Brainiac to find out that Kent is Superman would
lead to the leveling of the Daily Planet, the torture of the Kents
in Smallville, the dismemberment of Jimmy Olsen, and acts too unspeakable to mention
being visited upon Lois Lane.
But not every hero has a secret identity. For instance, the identities
of the Fantastic Four are common knowledge to general populace.
Rather than choosing a masked existence, the members of the original
superhero team in the Marvel Universe are open about who they are,
trusting that their powers and lifestyle will protect those they love.
Others have no alternate identity at all. Arthur Curry is the
real name of Aquaman, but he keeps no alternate life under that name.
Likewise, the Asgardian Thor though he has had alternate identities
in the past like Donald Blake and Sigard Jarlson and lead
a shared existence with humans like Jake Olsen has no real
alternate identity.
As well, the secret identity is not limited to superhero fiction.
Lamont Cranston is the other identity of the pulp hero the Shadow.
As well, Zorro lived his normal life as Don Diego del la Vega. | 
