Jason Todd in the context of "Tim Drake"

Robin is the alias of several superheroes appearing in American comic books published by DC Comics. The character was created by Bob Kane, Bill Finger, and Jerry Robinson to serve as a junior counterpart and the sidekick to the superhero Batman. As a team, Batman and Robin have commonly been referred to as the Caped Crusaders and the Dynamic Duo. The character's first incarnation, Dick Grayson, debuted in Detective Comics #38 (April 1940). Conceived as a way to attract young readership, Robin garnered overwhelmingly positive critical reception, doubling the sales of the Batman titles. Robin's early adventures included Star Spangled Comics #65–130 (1947–1952), the character's first solo feature. He made regular appearances in Batman-related comic books and other DC Comics publications from 1940 through the early 1980s, until the character set aside the Robin identity and became the independent superhero Nightwing.

The character's second incarnation, Jason Todd, first appeared in Batman #357 (1983). He made regular appearances in Batman-related comic books until 1988, when he was murdered by the Joker in the storyline "A Death in the Family". Jason was resurrected following a reality-changing incident, eventually becoming the Red Hood. The premiere Robin limited series was published in 1991, featuring the character's third incarnation, Tim Drake, training to earn the role of Batman's vigilante partner. After two successful sequels, the monthly Robin series began in 1993 and ended in early 2009, which also helped his transition from sidekick to a superhero in his own right. In 2004 storylines, established DC Comics character Stephanie Brown became the fourth Robin for a short time before the role reverted to Tim Drake. Damian Wayne succeeds Drake as Robin in the 2009 story arc "Battle for the Cowl."

The Joker is a supervillain appearing in American comic books published by DC Comics. Created by Bill Finger, Bob Kane, and Jerry Robinson, the character first appeared in the debut issue of the comic book Batman on April 25, 1940. Credit for the Joker's creation is disputed; Kane and Robinson claimed responsibility for his design while acknowledging Finger's writing contribution. Although the Joker was planned to be killed off during his initial appearance, he was spared by editorial intervention, allowing the character to endure as the archenemy of the superhero Batman.

In the DC Universe, the Joker is portrayed as a criminal mastermind and the antithesis of Batman in personality and appearance. He was introduced as a murderous psychopath with a warped, sadistic sense of humor but became a comical prankster in the late 1950s in response to regulation by the Comics Code Authority, before returning to his darker roots during the early 1970s. The Joker has been part of defining Batman stories, including the murder of Jason Todd—the second Robin and Batman's ward—in "A Death in the Family" (1988) and the paralysis of Barbara Gordon—the first Batgirl—in The Killing Joke (1988). Unlike many comic book characters, the Joker does not have a definitive origin story, but various possible ones have been developed. The most common story involves him falling into a tank of chemical waste that bleaches his skin white, turns his hair green and lips red, and leaves him with a rictus grin; the resulting disfigurement drives him insane.

Damian Wayne (né al Ghul) is a superhero appearing in American comic books published by DC Comics, commonly in association with Batman. He was created by Grant Morrison and Andy Kubert. Damian Wayne is the biological son of Bruce Wayne/Batman. His mother is Batman's love interest Talia, daughter of Batman's adversary Ra's al Ghul, who wants Bruce Wayne to sire his future lineage. Talia calls off their marriage once she falls pregnant and tells Bruce she miscarried, keeping Damian's existence hidden until Batman #656 (2006). Damian was intended to kill and replace Batman and serve as a host body for Ra's al Ghul, which would unify the Wayne and al Ghul factions. Damian is Bruce's youngest child and only biological one, with Dick Grayson, Jason Todd, Tim Drake, and Cassandra Cain as his adopted siblings.

A prototype of the character originally appeared as an unnamed infant in the 1987 story Batman: Son of the Demon, which at the time was not considered canon. Following this, various alternate universe stories dealt with the character's life, giving him various names. In 2006, the character was reinterpreted as Damian Wayne by Grant Morrison, and introduced into the main continuity in Batman #655, the first issue of the "Batman and Son" story arc. Damian Wayne is the fifth character to assume the role of Robin, Batman's vigilante partner.

Richard John "Dick" Grayson is a superhero appearing in American comic books published by DC Comics, commonly in association with Batman, the Teen Titans, and the Justice League. Created by writer Bill Finger and artist Bob Kane, he first appeared in Detective Comics #38 in April 1940. Dick is the original and most popular incarnation of Robin, Batman's crime-fighting partner – together known as the Dynamic Duo. In his origin story, he is the orphaned son of master acrobats the Flying Graysons who is later adopted by Batman's alter ego Bruce Wayne.

Dick Grayson has undergone significant character development since originally introduced in 1940. In 1984, he graduated from the role of Robin to become the adult superhero Nightwing, protector of the city of Blüdhaven, Gotham City's economically troubled neighbouring city. Since then, as Bruce's eldest son, Dick has taken on an older brother figure to his male successors as Robin – tearaway Jason Todd, teenage prodigy Tim Drake, and trained assassin Damian Wayne, who is also Batman's biological child. Among other members of the Batman Family, his closest relationships are with Batman's loyal butler and father figure Alfred Pennyworth, and with his romantic interest Barbara Gordon, who served as Batgirl alongside Dick as Robin, and who later aids Nightwing as Oracle. Dick has also taken up the mantle of Batman himself on a number of occasions when Bruce was missing, incapacitated, or believed dead.

"A Death in the Family" is a 1988 storyline in the American comic book Batman, published by DC Comics. It was written by Jim Starlin and penciled by Jim Aparo, with cover art by Mike Mignola. Serialized in Batman #426–429 from August to November 1988, "A Death in the Family" is considered one of the most important Batman stories for featuring the death of his sidekick Robin at the hands of his archenemy, the Joker.

Jason Todd, the second character to assume the Robin persona, was introduced in 1983 to replace Dick Grayson, who was unavailable for use at the time. Jason became unpopular among readers after 1986, as writers began to characterize him as rebellious and impulsive, and Starlin advocated killing him off. Editor Dennis O'Neil was considering having Jason revamped or written out of Batman when he recalled a 1982 Saturday Night Live sketch in which Eddie Murphy encouraged viewers to call the show if they wanted him to boil a lobster on air. Inspired to orchestrate a similar stunt, DC set up a 900 number voting system to allow fans to decide Jason's fate.