Gotham Knights Breaks The Oldest Batman Rule With The Joker

Warning: The following contains SPOILERS for the Gotham Knights premiere.The pilot episode of Gotham Knights confirms that the Batman of this reality broke his classic rule and killed The Joker. This continues a trend in recent Batman adaptations, where the Dark Knight's use of lethal force is meant to set it apart from more traditional interpretations. In the case of Gotham Knights, however, it also serves to increase the tension between two of its lead characters.
The Gotham Knights show is set on an Earth quite different from the classic Gotham City, where Bruce Wayne adopted a boy named Turner Hayes after the violent deaths of Turner's parents. Turner is shocked by the revelation that Bruce Wayne was Batman, after his father is found dead wearing Batman's cowl. Despite this, Turner is accused of masterminding the crime after the GCPD discover his bank account was used to pay the accused killers. This leads to Turner being arrested and confined with the teenagers accused of Bruce Wayne's murder, and his discovery that one of them might have a motive for killing Batman beyond money.