Riddle Me This

When is a Riddle not a Riddler? Riddle me this, Robin! Who sings for Nightwing? Friend or foe? The Riddler. He’s a constant thorn in Batman and Robin’s side who always teases the Caped Crusader and Boy Wonder with enigmas and questions pertaining to his master plan, but is the Riddler truly a villain or a hero? Can the king of conundrums turn over a new leaf to become a master detective and crime-fighter himself?