been interested in comic books. This also led to an avalanche of other comic book adaptations which included previously lesser known Vertigo titles, notably Constantine (based on the comic book Hellblazer) and V for Vendetta. Rise of antiheroes In the mid-1980s, Marvel antiheroes such as the X-Men's Wolverine, the Punisher, and writer/artist Frank Miller’s darker version of Daredevil challenged the previous model of the superhero as a cheerful humanitarian. Miller also created Elektra, who straddled the conventional boundary between love interest and villain. Two artistically influential DC Comics limited series contributed to the trend: Batman: The Dark Knight Returns, also by Frank Miller and Watchmen by Alan Moore and Dave Gibbons, both of which were series of psychological depth that starred troubled heroes. By the late 1980s DC had published many mature titles such as John Constantine, Hellblazer, Swamp Thing, and Lobo. They featured morally ambiguous characters such as the cynical John Constantine and the violence-loving Lobo with graphic violence and adult content that differentiated them from other mainstream titles. DC later separated these titles to their launched Vertigo imprint that publishes titles outside of the DC Universe. By the early 1990s, antiheroes had become the rule rather than the exception, and among the most popular were Marvel Comics' Cable and Venom and Image Comics' Spawn. The trend of creating characters with more psychological depth that were less black-and-white, also affected supervillains. For example, the Joker, Batman's nemesis, was portrayed less as an evil criminal and more as a mentally ill psychopath who cannot control his actions, Marvel Comics' galactic planet-eater Galactus became a force of nature who means no personal malice in his feedings, and the X-Men's nemesis Magneto became more benign and sympathetic as a man who fights for an oppressed people, albeit through means that others deem unacceptable. Development of the X-Men franchise By the mid-1980s, X-Men had become one of the most popular titles in comics. Marvel decided to build on this success by creating a number of spin-off titles, sometimes collectively referred to as "X-Books". These early X-Books included New Mutants (which would later become X-Force), X-Factor, Excalibur, and a Wolverine solo series. There were many new popular additions to the X-Men in the 1990s, including Cable and Bishop. By the early 1990s, X-Men had become the biggest franchise in comics, and by the middle of the decade over a dozen X-Men-related comic books, both