However, a return of darker plot elements and storylines more related to relevant social issues began to flourish during the period, prefiguring the later Modern Age of Comic Books.

[2][3] Later in 1970, Jack Kirby left Marvel Comics, ending arguably the most important creative partnership of the Silver Age (with Stan Lee).

Kirby then turned to DC, where he created The Fourth World series of titles, starting with Superman's Pal Jimmy Olsen #133 in December 1970.

The beginning of the Bronze Age coincided with the end of the careers of many of the veteran writers and artists of the time, or their promotion to management positions and retirement from regular writing or drawing, and their replacement with a younger generation of editors and creators, many of whom knew each other from their experiences in comic book fan conventions and publications.

At the same time, publishers began the era by scaling back on their superhero publications, canceling many of the weaker-selling titles, and experimenting with other genres such as horror and sword and sorcery.

Conan's success as a comic hero resulted in adaptations of other Howard characters: King Kull, Red Sonja and Solomon Kane.

Marvel also adapted to comic book form, with less success, Edwin Lester Arnold's character Gullivar Jones and, later, Lin Carter's Thongor.

The murder of Spider-Man's longtime girlfriend, Gwen Stacy, at the hands of the Green Goblin in 1973's Amazing Spider-Man #121–122 is considered by comics scholar Arnold T. Blumberg to be the definitive Bronze Age event, as it exemplifies the period's trend towards darker territory and willingness to subvert conventions such as the assumed survival of long-established, "untouchable" characters.

However, there had been a gradual darkening of the tone of superhero comics for several years prior to "The Night Gwen Stacy Died", including the death of her father in Amazing Spider-Man #90 and the beginning of the Dennis O'Neil/Neal Adams tenure on Batman.

The positive reception that the story received led to the CCA revising the Comics Code later that year to allow the portrayal of drug addiction as long as it was depicted in a negative light.

Written by Denny O'Neil with art by Neal Adams, the storyline was entitled "Snowbirds Don't Fly," and it revealed that the Green Arrow's sidekick Speedy had become addicted to heroin.

In their place, they experimented with a wide variety of other genres, including Westerns, horror and monster stories, and the above-mentioned adaptations of pulp adventures.

Other well-known "relevant" comics include the "Demon in a Bottle", where Iron Man confronts his alcoholism, and the socially conscious stories written by Steve Gerber in such titles as Howard the Duck and Omega the Unknown.

Characters such as Luke Cage, Mantis, Misty Knight, Shang-Chi and Iron Fist have been seen by some as an attempt by Marvel Comics to cash in on the 1970s crazes for kung fu films.

By the mid-1980s, Storm and Cyborg had become leaders of the X-Men and Teen Titans, respectively, and John Stewart briefly replaced Hal Jordan as the lead character of the Green Lantern title.

One of the most apparent influences from this series was the creation of what became DC Comics' answer to X-Men's character-based storytelling style, The New Teen Titans by Marv Wolfman and George Pérez, which became a highly successful and influential property in its own right.

Another title, The Avengers vs. the Justice League of America was written by Gerry Conway and drawn by George Pérez with plotting by Roy Thomas, but was never published, reflecting the later animosity between the two companies.

Marvel eventually gained 50% of the market and Stan Lee handed control of the comic division to Jim Shooter while he worked with their growing animation spin-offs.

As previously noted, 1971's revised Comics Code left the horror genre ripe for development and several supernaturally-themed series resulted, such as the popular The Tomb of Dracula, Ghost Rider and Swamp Thing.

During this period, Charlton, Western Publishing/Gold Key, Marvel and DC also regularly published official comic book adaptations for various projects, including popular films (Planet of the Apes, Godzilla, Logan's Run, Indiana Jones, Jaws 2, 2001: A Space Odyssey, Star Wars), TV shows (The Six Million Dollar Man, Lost in Space, The Man from Atlantis, Battlestar Galactica, Star Trek, The A-Team, Welcome Back Kotter), toys (G.I.

Joe, Micronauts, Transformers, Rom, Atari Force, Thundercats), and even public figures (Kiss, Pope John Paul II).

An 'explicit content' market akin to the niche Underground Comix of the late '60s was ostensibly opened with the Franco-Belgian import Heavy Metal Magazine.

Marvel launched competing magazine titles of their own with Conan the Barbarian and Epic Illustrated which would eventually become its division of Direct Sales comics.

Other small-press publishers came in to take advantage of this growing market: Pacific Comics introduced in 1981 a line of books by comic-book veterans such as Jack Kirby, Mike Grell and Sergio Aragonés, for which the artists retained copyright and shared in royalties.

In 1978, Will Eisner published his "graphic novel" A Contract With God, an attempt to produce a long-format story outside the traditional comic book genres.

During this period Marvel published the crossover Secret Wars, cancelled Defenders and Power Man and Iron Fist, and launched the New Universe and X-Factor (an extension of the X-Men franchise).

According to Shawn O'Rourke of PopMatters, the shift from the previous ages involved a "deconstructive and dystopian re-envisioning of iconic characters and the worlds that they live in",[5] as typified by Frank Miller's Batman: The Dark Knight Returns (1986) and Alan Moore's and Dave Gibbons' Watchmen (1986–1987).