Content Warning: This article contains a discussion of darker themes.
Disney+'s Loki is exploring alternate timelines in the MCU for the first time, but Marvel Comics has been doing it for decades. While some of Loki's timelines have shown to be very dark so far, the comic books feature so many dark, dystopian timelines that it's hard to determine which is the darkest of them all.
Some of the darkest timelines in the comics may end up being critical in the MCU as the franchise moves forward, with Loki beginning to play with the multiverse and the concept set up to be a major component of Phase 4. Exploring the nightmarish alternate timelines in the comics might provide some hints as to which directions the MCU is going in.
God Of Thunder
In 2012, writer Jason Aaron and artist Esad Ribić began the "God Of Thunder" story arc, which featured three separate timelines for Thor - past, present, and future.
In the future, Thor had become King of Asgard but was mostly alone as Gorr The God Butcher had slain nearly all other gods. It's possible Loki visits some version of this timeline, or it could appear in the upcoming movie Thor Love And Thunder as well.
Age Of Apocalypse
One of the most brutal timelines involves the X-Men and it's arguably not even their darkest. The "Age Of Apocalypse" storyline from the '90s saw an alternate reality where Professor X died early in his quest for peace and justice and Apocalypse conquered the Earth by wiping out much of mankind.
Magneto leads a very different X-Men in a bloody battle to save the earth and ultimately the universe. While the X-Men are still far off in the MCU, a tease of this timeline is certainly possible upcoming, given the mutant-related fictional country of Madripoor has already been introduced.
Marvel Zombies
Things get dark in a hurry whenever there are zombies involved, as seen in movies like Army Of The Dead. The same is true in Marvel Comics. An entire alternate universe exists of Marvel Zombies where the undead run amok over the world, and turn some of the greatest superheroes and villains into zombies.
In the story, the superheroes end up eating all non-infected people, leaving them without any food supply. This timeline began in a limited series in 2005 and has been revisited a few times since, most notably in the 2015 Secret Wars crossover, which Loki may actually contain a connection to.
Hulk: The End
Hulk: The End is a special one-shot issue written by long-time Hulk writer Peter David and drawn by Dale Keown. Part of a series of specials featuring 'the end' of major superheroes, this story depicts the Hulk as the only survivor on Earth after a nuclear war decimates all of humanity.
It is a very dark and somber story, with Bruce Banner ready to succumb but the powerful - and essentially indestructible - Hulk refusing to. Their battle of wills leads to their greatest battle of all, between one another.
House Of M
House Of M is one of the comic book storylines that inspired WandaVision. This seminal 2005 storyline saw Wanda Maximoff, the powerful Scarlet Witch, erase the majority of mutants with a single phrase. Only 198 mutants were left with their powers at the end of the story.
The consequences of that are still playing out in the comics today, and the storyline could serve to further inform the MCU. With Wanda possibly looking for her children, Tommy and Billy Maximoff, her journey could lead her through the multiverse to many other timelines.
Spider-Man: Reign
In the alternate future of Spider-Man: Reign, Mary Jane Watson has died from cancer she received from Peter Parker's radioactive bodily fluids.
It's a very dark story for the Wall-Crawler and a comic book storyline that is probably best avoided for the MCU. The story also has New York City under strict control by a tyrannical mayor. He ultimately sends the most powerful members of the Sinister Six after Peter Parker, leading to one of their most brutal battles in the comic books.
Age Of Ultron
Age Of Ultron is a 2013 crossover that imagines a dark alternate timeline where Ultron conquerors the world. He launches an all-out assault against major cities and unleashes armies of drones to patrol the world. The circumstances of this world are very different.
Janet Van Dyne, the Wasp, is this reality's version of Captain Marvel, for instance. She's also a victim of its relentless darkness, killed along with many other Avengers and New Yorkers in a nuclear explosion. Wolverine ultimately goes back in time to stop Ultron from conquering the world.
King Hyperion
Hyperion is the leader of the Squadron Supreme, the team at the core of the recent alternate reality comic event Heroes Reborn. But that isn't the darkest timeline he's associated with. In the alternate reality of Earth-4023, Hyperion becomes king of the Earth after declaring himself ruler and killing all of its heroes.
Hyperion, whose powers are based largely on Superman's, defeated even the most powerful heroes like Hulk and Thor. In the end, the story becomes even darker as humanity annihilated itself with nuclear weapons to escape him.
Days Of Futures Past
One of the first and most significant alternate timelines in Marvel Comics is "Days Of Futures Past." In this dark future, Sentinels have hunted down and killed nearly all mutants, with the survivors placed in camps. Kitty Pryde travels back in time into her younger self to warn the X-Men of the future. Many of the X-Men in the future, including Wolverine, are killed.
Though it only lasted for two issues, the storyline would have massive ramifications for the comics in the years to come, including the introduction of Rachel Summers, the alternate future daughter of Scott Summers and Jean Grey.
Old Man Logan
One of the absolute darkest timelines in Marvel Comics belongs to Old Man Logan. In this future, superheroes have been largely wiped out and supervillains rule the world. Wolverine is hiding, after a disastrous incident in which he slaughtered the X-Men while under the influence of Mysterio, who comic fans know is typically a Spider-Man villain.
Logan ultimately goes up against an insane super powerful Hulk in one of the darkest and most disturbing comic book storylines to feature the characters.