The Joker- Batman: A Death in the Family

Batman: A Death in the Family, an epic event in comic history, was written by Jim Starlin with art by Jim Aparo and Mike DeCarlo. The story arc took place from 1988-1989 in Batman #426 - Batman #429. The book surrounds Jason Todd, the second Robin, as he tries to track down his birth mother. The Joker has escaped from Arkham Asylum and is selling nuclear weapons to terrorist groups. Robin, distracted with personal issues, is barely any help to Batman in tracking The Joker. 

Robin confronts Sharmin Rosen, a Mossad agent, in Lebanon but she denies parenting a child. Batman and Robin give Lady Shiva a truth serum, following a fight that Batman nearly loses, to discover that she, too, is not Robin's mother. 

In Ethiopia, Batman & Robin meet an aid worker from Gotham named Sheila Haywood. She is revealed to be Jason Todd's birthmother. It is revealed that Sheila has a villainous past and is being blackmailed by The Joker. She sends The Joker medical supplies from her aid agency's warehouse so he can sell them on the black market. The Joker replaces the medicine with laughing gas, killing hundreds. As part of their deal, Sheila hands Robin (her son) over to The Joker as a prisoner. 

The Joker beats Jason Todd with a crowbar until he is unconscious and ties him up, along with Sheila, in a warehouse laced with explosives. When the bomb goes off Robin throws himself on top of his mother in an attempt to save her, and dies in the explosion. 

Batman: A Death in the Family is a significant defeat for Batman and it is especially important because readers were given a 900 number to call to vote on whether Robin should live or die.