It was going to happen sooner or later. You can't send children to fight psychopaths for over 40 years without something going wrong, and in the groundbreaking Batman arc A Death in the Family, Batman finally pays for years and years of child abuse.
Of course, as always, it's really Robin who gets the short end of the stick. In the story's biggest moment, Joker beats Jason Todd, the second Robin, with a crowbar, and then traps him inside a building with a ticking time bomb. The bomb goes off before Batman arrives, and Robin dies in the blast.
While that sounds like Robin's death is the Joker's fault (and, to be fair, the Clown Prince of Crime plays a major role in Jason's demise), it all comes down to Batman, who made mistakes with Jason from the very beginning. When Batman discovers that Jason's father was murdered by Two-Face, he keeps it a secret—and when Jason learns the truth, he's furious. From that moment on, Jason doesn't trust Batman, and so when Jason's birth mother is kidnapped by the Joker, he disobeys Batman's orders and goes after the supervillain on his own.
In the aftermath, Batman admits Jason was too young and impulsive to be Robin—but that didn't stop Bruce from putting him in a domino mask anyway. "I felt so adrift when I lost Dick Grayson as a partner," Batman laments. "I guess the truth is that I was lonely... didn't want to go it alone." And so, Batman hired Jason, and Robin lost his life—something that happened again in 2013, when an assassin killed the fourth Robin, Damian Wayne, and yet again in 2016, when Tim Drake sacrificed his life to save Gotham City.
