Heroic identities that have been used by more than one character; usually these are comic book superheroes, and often these identities are passed down through generations in a family of do-gooders.

To be a Legacy Hero it doesn't specifically mean these characters are deceased although it normally does require that a character - usually the bigger good - has died and generations to come will take up his mantle these can just be heroes who went into hiding and trained a new hero to follow his path.