The Legion of Super-Heroes

Among the Legion's many members are Bouncing Boy, Brainiac 5, Chameleon Boy, Cosmic Boy, Element Lad, the Invisible Kid, Mon-El, Lightning Lad, Saturn Girl, Sun Boy, and Triplicate Girl.  When Superman was a teenager (see Superboy), he journeyed into the future and joined the Legion.  Supergirl is also a member of the Legion.  Jimmy Olsen is an honorary member of the Legion under the name Elastic Lad.  The Legion's "animal branch" is known as the Legion of Super-Pets.  The Legionnaires are fully aware that Clark Kent is secretly Superman.

Since Superman has the power to travel in time, it is possible for him to journey to the thirtieth century A.D. to visit the Legion either during the period when they are teen-agers or during the period when they are adults.  By the same token, since the Legionnaires are able to time-travel also, it is possible for them to return to the twentieth century to visit Superman either as teen-agers or as adults.  For this reason, the Legionnaires appear in the chronicles sometimes as teen-agers and sometimes as adults.  And as adults, the Legionnaires often have different names from the ones they employed as teen-agers.  The adult Cosmic Boy is called Cosmic Man the adult Lightning Lad is called Lightning Man; the adult Saturn Girl is called Saturn Woman; and so on.