When last we left off, Secret Wars was a massive success, which meant, of course, one thing: Secret Wars II. Unlike the Gold, Silver, and Bronze Ages, however, the Dark Age of Comics is nebulous at best — some people state that it started after the publication of Watchmen and Dark Knight Returns, when comics took a turn for the dark and gritty. Some claim that the Bronze Age ended with Crisis on Infinite Earths or Alan Moore's "Whatever Happened to the Man of Tomorrow?"
But this is about Marvel and crossovers, so let us just say that the Dark Age started with Secret Wars II. Because, while the first Secret Wars was silly but fun, the second was something much different.
For one thing, it wasn't confined to its own nine-issue limited series. By this point, crossovers came in two versions: the limited series and the cross-through, which started in one book and went through other various books. Secret Wars II did both. It didn't just cross into Captain America and Iron Man, it crossed into nearly every single book out at the time, including Alpha Flight, Dazzler, and ROM.
(Twelve years later, it would also crossover with Deadpool Team-Up #1. Don't ask.)
Unlike the previous Secret Wars, there was no Battleworld. In fact, there weren't really any wars. The Beyonder just seemed to wander around causing trouble. In Amazing Spider-Man, he turned a building into gold and had to be taught by Spider-Man how to poop. In one issue, the Beyonder falls in love with Dazzler. The entire thing ended when the Beyonder's energies are sent out to create a new universe.
Secret Wars II wasn't the only reason that crossovers became popular however. The other cause was the X-Men explosion (or "x-plosion" if you want to be cute): Uncanny X-Men already had a few spin-offs, like Alpha Flight and Dazzler, but in the late '80s, the number of spin-offs LEAPED. Soon, there was The New Mutants, X-Factor, X-Terminators, Excalibur, and more. Though this wasn't limited to the X-Men, they certainly had the most spin-offs. This led to more and more crossovers, starting with Mutant Massacre and then Fall of the Mutants.
Despite the fact that these stories were darker (this is the Dark Age), they were still considered good and often included some of the best writing in the '80s and '90s.
Interesting enough, Fall of the Mutants isn't a cross-through — each part of the crossover is completely separate and can be read independently. The storyline involved each team of mutants going through terrible ordeals. The crossover that came after it, Inferno, however, was massively interconnected, even to books outside of the X-Men books.
There were also what was called "Annual" crossovers — storylines that ran through various summer annuals. The first such story was 1988's The Evolutionary War and then the next year it was Atlantis Attacks.
Then, in 1989, there was Acts of Vengeance, a crossover that involved Loki gathering up a large group of supervillains to defeat the Avengers. Compared to the previous crossovers that focused on the X-Men, there wasn't much substance to this one. The one bright spot was Captain America #367, where Magneto gets revenge on the Red Skull by imprisoning him in an underground crypt. It was awesome.
Crossovers had become an annual event. Since they sold so well for the X-Men, most of the crossovers became X-Men crossovers: there was X-Tinction Agenda (1990-1991), the Muir Island Saga (1991), X-Cutioner's Song (1992-1993), and Fatal Attractions (1993), where in a meeting of writers, Peter David infamously said about a fight between Magneto and Wolverine, "Why doesn't he just rip out his skeleton?"
Interspersed with these was Jim Starlin's limited series involving cosmic heroes and villains, primarily Warlock and Thanos. The story started with an issue of Silver Surfer that resurrected Thanos for a two-issue mini-series, The Thanos Quest, in October 1990. This then led directly to The Infinity Gauntlet which had the Mad Titan assemble the titular gauntlet and kill half the universe.
The next year, 1992, had a sequel was called The Infinity War. It involved the Magus, Warlock's evil side, trying to conquer the universe with an army of evil doppelgangers and the first issue had one of the more famous fold-out covers (look at the whole thing here).
The third part of the trilogy in 1993 was called The Infinity Crusade and involved Warlock's "good side" (which is kind of debatable), the Goddess, kidnapping and brainwashing various heroes to fight in her holy war.
The Marvel Year in Review for 1993 contained this great quote:
"It must be like an annual convention for super heroes that Warlock runs for them. It gives them all a chance to get together and network and catch up on each other's continuity, exchange business and trading cards, pose for holograms with each other, stuff like that. They probably just wish the things were held in San Diego or someplace fun, where everyone could hang out at the beach."
If you think we're at Peak Crossover, well, you ain't seen nothing yet. Acts of Vengeance? Infinity Gauntlets? Pfft. Soon after the Infinity Crusade was over, the X-Men went through a crossover called Legion Quest which ended with Professor X's son Legion accidentally killing his own father in the past.
Welcome to the Age of Apocalypse. Beginning with X-Men: Alpha in January 1995, every single X-Men comic was replaced with an Age of Apocalypse version. Generation X became Generation Next, X-Factor became Factor X, Excalibur became X-Calibur, X-Force became Gambit and the X-Ternals, Wolverine became Weapon X, Cable became X-Man, Uncanny X-Men became Astonishing X-Men, and X-Men became Amazing X-Men.
Even though everything reverted back at the end, there were still consequences. Some characters, including X-Men and Dark Beast, crossed over into the regular universe. One character, Blink, was brought back later on to head up a team of alternate universe characters called Exiles.
Then, in 1996, two things happened: Marvel tried to revive their non-X-Men characters by including them in a massive crossover called the Onslaught Saga. Onslaught was a combination of Professor X and Magneto's minds and, while the crossover mainly involved the X-Men, it reached out and pulled in other books, books that Marvel saw were no longer selling as well.
So Marvel killed them off and handed them over to the creators of Image comics. This became Heroes Reborn.
The other thing that Marvel did? They declared bankruptcy.
Heroes Reborn wasn't the big seller that Marvel hoped it would be. In fact, it only lasted one year before Marvel pulled the plug and brought the heroes back in an event called Heroes Return, which explained everything away with Franklin Richards, who had created a pocket Counter Earth. Marvel dragged themselves out of bankruptcy and handed the Avengers off to Kurt Busiek.
Some say that the Dark Age of Marvel ended with the publication of Avengers Vol. 3 #1, the beginning of the highly acclaimed Kurt Busiek/George Perez run.
Some say that the Dark Age of Marvel ended after another X-Men crossover, Eve of Destruction, when the X-titles were all reorganized and the New X-Men run by Grant Morrison and Frank Quitely began.
Some say the Dark Age of Marvel only ended with the publication of Ultimate Spider-Man #1 in October 2000 or in 2001 when Marvel stopped publishing with the Comics Code Authority or with the creation of Marvel MAX.
Some say that the Dark Age never ended.
But let's not think about that. A new era of crossovers was upon Marvel. A new millennium. A new age:
The Modern Age.
(PS: I know I left some crossovers out, like Operation: Galactic Storm or the Clone Saga. But there were just SO MANY. I had to pick and choose!)