The Riddler (Edward Nigma) is a fictional supervillain appearing in American comic books published by DC Comics, commonly as an adversary of the superhero Batman. The character made his first appearance in Detective Comics #140 (October, 1948) and was created by Bill Finger and Dick Sprang. Depicted as a Gotham City criminal mastermind, the Riddler takes delight in incorporating riddles and puzzles into his plots, and leaves them as clues for the authorities and Batman to solve. The character is one of Batman's most enduring enemies and belongs to the collective of adversaries that make up Batman's rogues gallery.

The Riddler makes his first true appearance in the new DC continuity relaunch, DC Rebirth, in Batman #19. An inmate of Arkham once again, he rather cooperatively assists Bane in unlocking a high tech door, allowing Bane access to confront Batman.  In the eight-part story-arc "War of Jokes and Riddles", commencing with Batman Vol. 3 #25, flashbacks to a year after the events of "Zero Year" have Batman recounting the details of a war between Riddler and Joker. He is first seen in custody at the GCPD, assisting them in solving a variety of crimes, including locating Joker's whereabouts, before stabbing a police officer to death 26 times. Blackmailing the approaching guards with details of their children and families, Riddler walks out freely before intruding into Joker's office. Riddler seemingly offers the Joker a partnership, acknowledging that if either of the two men individually kill Batman, the other will be left forever unsatisfied. However the Joker shoots Riddler in the stomach and quickly departs, Batman appearing through the window and giving chase. Left in a pool of his own blood, Riddler rose to his feet and limped out of the office, seemingly unfazed.  Edward quickly healed from the wound, carving a question marked shaped scar over the wound, before murdering Dr. Jaime Knowles. Riddler is then seen meeting with Poison Ivy, discussing the Joker's need to rid anyone who could potentially kill Batman before him. The duo are then ambushed by gunmen working for Carmine Falcone under the orders of the Joker to kill Riddler within the hour. However Poison Ivy attacks the gunmen with her vines, allowing Edward and herself to leave.  Riddler eventually formed his team, consisting on himself, Poison Ivy, Scarecrow, Deathstroke, Clayface, Killer Croc, Two-Face, Firefly, and Victor Zsasz. Waging war on Joker's team across Gotham, Riddler is responsible for poisoning Charles Brown's son, resulting in his transformation into Kite Man who joins up with Joker's team consisting of Cluemaster, Deadshot, Mad Hatter, Man-Bat, Mr. Freeze, Penguin, Solomon Grundy, and Ventriloquist. The war continues, with Riddler and Joker claiming territories across Gotham, before Riddler, who'd convinced Batman to side with him during the conflict, blackmails and interrogates Kite Man into giving up Joker's location. However Batman, after a brief fight between him, Riddler and Joker, becomes disgusted by Riddler's actions and quickly grabs a blade, breaking his one rule of No Killing in order to stab Riddler. However Joker, who finally begins to laugh again, prevents Batman from doing so.  The present day Riddler shows up next in 'Deathstroke #25' as a member of The Society who have placed Deathstroke on trial for appearing to have reformed. Riddler, using Hector Hammond's abilities, convinces the Society that Deathstroke is indeed evil by showcasing a simulation of Deathstroke killing them all right before Deathstroke himself is kidnapped.

Answer the following question by taking a quote from the article: Are there any other interesting aspects about this article?
Blackmailing the approaching guards with details of their children and families, Riddler walks out freely before intruding into Joker's office.