There are many heroes in society: one which we all think is the best. But in reality they share if not similar, the same characteristics. They are all unique in some way, most are martyrs and have a fatal "Achilles Heel" which their opponent will exploit to defeat them.
Firstly, heroes all have a unique factor that sets them apart from society at large. Some, like Master Chief, have a special suit or item that enhances their capabilities far beyond those reachable by a human. Heroes also may have a special skill that humans will never have like Gandalf who wields powers ancient and great that can banish evil demons to the pits of hell from whence the came.
Secondly, heroes will commit themselves to a quest and sacrifice themselves to see thee task actualized; marine Sergeant Joe Enders (Wind talkers) sacrifices himself to retrieve the platoon's radio; saving the wounded and pinned down platoon.
Heroes are also martyred in the pursuit of an ideal, for example giving their live in order to restore freedom, as William Wallace did, even when he is captured by the duplicitous King Longshanks, he dies on the torture rack uttering one final word "freedom!"
Finally, heroes possess a fatal flaw, which their foe will often exploit in an attempt to destroy them. This is evidenced by James Bond, who has an appetite for phenomenally beautiful woman, a fact which his foe will often use to their advantage, either using the women as bait or getting them to pull a gun on Bond. Other heroes are often guilty of possessing a similar flaw, Boromir for example had a desire to save his native Gondor using the One Ring, rather than destroy it, this desire opens him to the One Rings fell...