When was Enigma - DC Comics created?

There isn't a DC Comics character named "Enigma" with a definitive creation date. It's possible you are thinking of one of these:

* The Riddler (Edward Nigma): The most famous "Enigma" character in DC Comics is the Riddler, a Batman villain who debuted in Detective Comics #140 (October 1948).

* Enigma (Alan Grant): There was a character named "Enigma" created by Alan Grant in the Batman: Shadow of the Bat #1 (June 1992) storyline. This character was a mentally unstable assassin who preyed on Gotham's elite. However, this character had limited appearances and isn't a major player in the DC Universe.

Therefore, it's important to clarify which "Enigma" you are asking about for a specific creation date.