The Riddler

The Riddler, otherwise known as "Edward E. Nigma" (or "Nygma") is a psychotic criminal from Gotham City, known for his riddles and being an enemy of Batman.

Known for his purple domino mask and green question mark-covered costume, either as a skintight cat suit or a business suit and bowler hat and his special question mark shaped cane, the Riddler is obsessed with riddles, puzzles, and word games. He delights in forewarning police and Batman of his capers by sending them complex clues.

Background
When he was a child, Edward Nigma was physically abused by his father, who was not willing to believe his son's brilliance; even after got high scores on certain tests, to which his father believes he cheated on and would beat him to get a confession, and possibly out of envy.

With that, Edward was always compelled to tell the truth to prove his innocense...which also expands to a further obsession with riddles.