After Tim went missing for three weeks, Batman discovered him at the abandoned Arkham Asylum, where it turned out The Joker tortured him for information and brainwashed him into being a mini-Joker.
The biggest thing Joker ever did that hurt Batman far more than anything else, was the killing of Jason Todd. Joker killing Jason was an iconic moment in comics and further developed Joker's relationship with Batman, but it turns out that originally, Joker never wanted credit for it at all.
Jason Todd, the former Robin killed by the Joker in Batman: A Death in the Family, is revealed to have been resurrected by Ra's al Ghul via the Lazarus Pit. But the pit changes him and his emotions and he becomes the new Red Hood. His debut culminates in a fateful confrontation with those he feels have wronged him.
Dick Grayson, formerly known as Robin, later known as the New Joker, is the main antagonist of Frank Miller's comic miniseries The Dark Knight Strikes Again. He was the former Robin, who turned into a murderous psychopath, because of Batman's actions to him as a child.
Batman has trained many young heroes as Robin, and while they have all been impressive on their own, DC just confirmed that one stands above the others in terms of power: Damian Wayne is the most powerful Robin.
Book(s) The murder of Robin was the execution of Batman's protégé, Robin, at the hands of the Joker and his second-in-command/girlfriend Harley Quinn.
Damian Wayne killed Nightwing in the comic book Injustice: God Among Us, where Superman goes insane when Joker manipulates him to kill his pregnant wife, Lois Lane. This tragedy prompts Superman to “police” everyone and ensures no crime is ever committed.
Dick Grayson became Nightwing after Batman fired him from his own mantle of Robin for getting shot by Joker. Grayson's Flamebird was Bette Kane. After The New Teen Titans, Nightwing teamed up with old friend Speedy in Action Comics #613-618 & #627-634 later collected in New Friends Old Enemies.
The series ended in controversy when the final issue suggested that Anarky was the biological son of the Joker. Originally a suggestion by Norm Breyfogle, the idea was advanced by Alan Grant as an attempt to solidify Anarky's role as a part of the Batman mythos.
J.J. or Joker Jr. is Tim Drake when he was brainwashed by The Joker in Batman Beyond: Return of The Joker.
With false implanted memories in his head, Dick Grayson becomes the Son of Joker, and it looks as though he just got a pretty gross inheritance in Red Hood and the Outlaws #48.
Jarro grew attached to Batman and even often calls him “father”. He wanted to prove to Batman that he can be the best Robin and even convinced Batman to give him a chance. Jarro became the new Robin and was even said to be Batman's favorite Robin, admitted by Batman himself.
Ultimately, Stephanie Brown's time with Batman ended because she was not willing to bend to his will and obey his very harsh rules; the same rules that led to all the Robins deciding that taking the name was a bad thing.
Damian Wayne is the son of Batman and Talia al Ghul. This makes him an heir to the world's greatest crime-fighter, and its greatest super-villain Ra's al Ghul. Damian became the fifth Robin, working alongside his father as Batman.
Killed the Joker
In Joker: Last Laugh #6, Nightwing is tricked into believing that the Joker fed Tim Drake to Killer Croc. Enraged at the (supposed) death of his surrogate brother, Nightwing beats the Joker to death.
Nightwing has a long career in crime fighting that has spanned many decades, but one thing that's remained consistent is his fear of failure, which was instilled by Batman.
DC's Batman: Beyond the White Knight reveals why Bruce Wayne/Batman married Harley Quinn within the "Murphyverse." Batman: Beyond the White Knight #2 ended with the surprising revelation that Bruce and Harley had tied the knot following the events of Batman: Curse of the White Knight.
Batman is known for suddenly appearing before criminals, but Damian Wayne can do it better - and underwater. Warning: contains spoilers for Superman: Son of Kal-El #14!
The first character to become Robin, Dick Grayson, defined the sidekick as we know him now, in his 44 years in the role: the endless puns and exclamations of “Holy … !”; the red, green and yellow tunic with a scaly speedo and pixie boots; the dependable pluckiness.
As Batman himself once said, “if I allow myself to go down into that place, I'll never come back.” In the 1989 film “Batman,” the Caped Crusader allows the Joker to fall to his death, although it is unclear whether this was a deliberate act or an accident.
1 DICK GRAYSON
Tim Drake may be everyone's favorite Robin, but there's no denying that Dick Grayson is the ultimate sidekick. Not only is he the first Robin, he's gone on to establish his own Nightwing persona and inherit the Batman mantle from his former protege more than anyone else inside the Bat-Family.
Richard "Dick" Grayson, mostly known as Robin, is one of main protagonists of the 2003 animated series Teen Titans. He is the leader and one of the five founding members of the Teen Titans.
Genius Level Intelligence: Robin is one of the intelligent characters of the Teen Titans series. However, he is often outsmarted by his arch-enemy, Slade. Skilled Detective: Due to his training from Batman, Robin is one of the greatest detectives of his generation.
Tim Drake may be the youngest of the Batman Family but he's also the smartest and a master of deductive reasoning. Tim is a true believer in Batman's mission and is motivated by the conviction that Gotham City needs a hero rather than by personal loss.