What is the Riddler's real name?

The Riddler's real name is Edward Nigma. The name is a deliberate pun on “enigma,” meaning something mysterious or difficult to understand, matching his obsession with puzzles and riddles.

The Riddler first appeared in Detective Comics #140 in October 1948, created by writer Bill Finger and artist Dick Sprang. He is usually portrayed as a criminal mastermind who stages elaborate crimes to prove that he is intellectually superior to Batman. His signature question marks, green clothing, domino mask, and phrase “Riddle me this” make him one of Batman's most recognizable enemies.

In some comic-book eras and adaptations, the surname is written as Nygma, while Edward Nashton is also used as an earlier or alternate identity. Those variations can cause confusion, but Edward Nigma is the classic canonical answer and the form used in many references to the character. In the Batman: Arkham games, he is commonly identified as Edward Nigma.