Although credited as "Billy Batson / Shazam" the character is never addressed on-screen by name. This is likely because of potential confusion for casual viewers who are not comic book readers. The character was originally named Captain Marvel and debuted in comics in 1940. Marvel Comics introduced a character called Captain Marvel in 1967 and over the years has created several other characters also called Captain Marvel. D.C. Comics eventually changed the character's name to Shazam. Similarly, the Wizard is never addressed by name (except in the first double episode, the wizard says to Billy Batson to call out my name to receive your powers to which Billy yells out SHAZAM & later Batman refers to him as the wizard Shazam.) . That character was originally named Shazam and saying his name transformed Billy Batson into Captain Marvel. In-universe the character died of extreme old age.