It started with a question to Gotham's star, Cory Michael Smith if the Riddler was instead a female.
So here comes my idea, (not going to mention Query and Echo).
What if Miss Kringle started off as the female Riddler, (I know this would throw everything off but just keep reading, please). Miss Kringle secretly always had a thing for Ed's riddles, but was too shy to admit to him as she was already with the officer as used as a cover up. Now that the two are seeing each other outside of work, Miss Kringle can finally have the courage and speak up.
Ed is dealing with multiple personalities due to rejections time after time which lead him become who he is at the time being.
Meanwhile, Miss Kringle shows off her puzzled plan to get her revenge on GCPD after for the death of her former lover whose revenge was never brought to justice as she thinks they were always busy with, "more important cases". As she snaps, Ed sees this side and gives her the code name, Labyrinth.
But she was accidentally shot by a misfired which led to Ed finally snap and let evil Ed completely take over to become, Riddler.
Like the idea, please let me know.