The Modern Age of Comics is a name for the age of comics from the mid-80's to present. In this age comic character were more psychologically complex and were darker. Creators were becoming more well known and independent comics started to become more popular.
The DC comic book maxi-series Crisis on Infinite Earths became the book that brought the Bronze Age and the Modern Age together. This brought the end to The Flash series, Superman series and the Wonder Woman series.
Fantasy, Horror, Mystery, and Suspense
Before the Modern Age horror and science fiction comics were not in mainstream comics but in the modern age the comics code was changed so then they made more Horror and Science Fiction comics because they could do more with it that they could not do before.
Alan Moore's legendary Swamp Thing run and Neil Gaiman's masterpiece The Sandman were some of the comics of the age which had Horror and Science Fiction elements in it.
Makeovers and universe reboots
The impact of Crisis on Infinite Earths was the first example as Supergirl died in issue #7, and long-time Flash (Barry Allen) died in issue #8. Specifically. His death was highly shocking at the time. Marvel Comics' Secret Wars would usher in a new change as well as Spider-Man would wear a black costume.
The interest in the speculator market of a new Spider-Man costume led to other changes for Marvel characters in the 1980s. Iron Man would have a silver and red armor. Captain America would be fired and would be reborn as the Captain, wearing a black outfit in #337 of the series. The Incredible Hulk would revert to his original Grey skin color. Issue #300 of the first Avengers series resulted in a new lineup including Mister Fantastic and the Invisible Woman, of the Fantastic Four.
Within the decade, Wolverine would switch to a brown and yellow costume, Thor would be replaced by Thunderstrike, Archangel would emerge as the X-Men's Angel's dark counterpart and many other Marvel characters would have complete image overhauls. The changes to Spider-Man, Thor, Captain America, Iron Man, Wolverine and most other Marvel characters would be undone in the early 1990s.
The 1990s would bring similar changes to the DC Universe, including the Death of Superman in 1992 and the Knightfall storyline in Batman comics, during which Azrael became the new Batman. Wonder Woman lost a challenge and Diana was replaced by Artemis as the new Wonder Woman until her death in issue #100. Guy Gardner went from being a Green Lantern to drinking from a chalice in a cave and becoming Warrior. The only change that would last for more than ten years was when Hal Jordan became Parallax and killed off all the Green Lanterns, resulting in Kyle Rayner becoming the new Green Lantern in issue #50 of the second series.
In addition to individual character or franchise/family wide makeovers, Crisis on Infinite Earths ushered in a popular trend of "rebooting", "remaking", or seriously reimagining the publisher wide universes every 5–10 years on varying scales. This often resulted in origins being retold, histories being rewritten, and so forth. These reinventions could be on as large a scale as suddenly retconning seminal story points and rewriting character histories, or simply introducing and/or killing off/writing out various important and minor elements of a universe. Crisis on Infinite Earths resulted in several mini-series which explicitly retconned character histories, such as Batman: Year One, Superman: Man of Steel, and Wonder Woman: Gods and Mortals.
An example of a less ambitious scale of changes is Green Arrow: The Longbow Hunters, which did not explicitly retcon or retell Green Arrow's history, but simply changed his setting and other elements of the present, leaving the past largely intact. This trend of publisher wide reinventions, which often consists of a new mini-series and various spinoff storylines in established books, continues today, with DC's recent Infinite Crisis and the spinoff storylines - One Year Later, 52, and Countdown to Final Crisis - and Marvel's House of M and Civil War storylines, the results of which are still being felt in the Marvel Universe.
Image Comics and creator rights disputes
In the mid-1980s, artist Jack Kirby, co-creator of many of Marvel's most popular characters, came into dispute with Marvel over the disappearance of original pages of artwork from some of his most famous titles. Alan Moore, Frank Miller, and many other contemporary stars became vocal advocates for Kirby.
By the early 1990s, these events, as well as the influence of vocal proponents of independent publishing, helped to inspire a number of Marvel artists to form their own company, Image Comics, which would serve as a prominent example of creator-owned comics publishing. Marvel artists such as X-Men’s Jim Lee, The New Mutants/X-Force’s Rob Liefeld and Spider-Man’s Todd McFarlane were extremely popular and were idolized by younger readers in ways more common to professional athletes and rock musicians than comic book artists.
Propelled by star power and upset that they did not own the popular characters they created for Marvel, several illustrators, including the above three formed Image Comics in 1992, an umbrella label under which several autonomous, creator-owned companies existed. Image properties, such as WildC.A.T.s, Gen¹³, Witchblade and especially McFarlane’s Spawn provided brisk competition for long-standing superheroes. Image in particular is singled out by some critics for contributing to the conditions which led to the speculator market crashing, as Image titles favored alternative covers, foil covers, and other "collectible" comics.
Many popular creators followed Image's lead and attempted to use their star power to launch their own series; ones for which they would have licensing rights and editorial control. Chris Claremont, famous for his long run as the writer of Uncanny X-Men, created Sovereign Seven for DC; Joe Madureira, also made popular by Uncanny X-Men, launched Battle Chasers for WildStorm Productions; and Kurt Busiek, Alex Ross and Brent Anderson created Astro City for Image.