It's worth noting that everything we've mentioned so far happened in the Golden and Silver Ages, but when DC rebooted their continuity in 1986, they wiped the slate clean for a new take on their complicated mythology. For Batman, the most famous example was his new origin story in Frank Miller and David Mazzucchelli's Batman: Year One, which kept the basics but updated it for the gritty crime wave of the '80s. The sequel, however, is far less well known—and completely buck wild.
Rather than making a stab at cowl-and-caped realism, Mike W. Barr, Alan Davis, and Todd McFarlane's Year Two was pure superhero drama, in which a murderous vigilante called the Reaper returned to Gotham after years of absence, with a brutality that even the Dark Knight couldn't stand against. In desperation, Batman decided to battle against the Reaper with a weapon he'd been holding in reserve for decades—the gun that killed his parents, lifted from the crime scene when he was a child—and struck a deal with Gotham's criminals to team up with their best triggerman: Joe Chill.
Batman's plan was to take down the Reaper and then turn the pistol on Chill in the ultimate act of poetic justice, but at the moment of truth, the decision of whether or not to kill his parents' murderer was taken from him when the Reaper did the deed instead. In the fight that followed, the Reaper was revealed to be the father of Batman's girlfriend, a story point that (very loosely) inspired the animated movie Mask of the Phantasm. Oh, and then there's a sequel to that story with a new version of the Reaper, who turns out to be Joe Chill Jr., out for revenge of his own. Comics are complicated, y'all.
