The Mighty Thor has used his prominent role in the Marvel Cinematic Universe to cement his reputation as one of Marvel's greatest and most popular superheroes, but Thor's comic book future is a bit murkier. Regular comic readers know Thor's character history spans decades in the real world and millennia in terms of Marvel continuity, and fans have occasionally gotten glimpses of what the far-flung future might hold for the God of Thunder.
One prominent storyline in this vein is the tale of "King Thor" - the almighty ruler of Asgard who has taken over Odin's throne and now oversees the entirety of the Nine Realms. That might sound awesome, but the reality of the King Thor timeline is actually pretty depressing.
The future setting of the King Thor storyline is rather bleak from the get-go. The Odinson sits on the throne of Asgard and watches over an Earth that has been bereft of humanity for thousands of years.
At some point in the past, Loki made yet another heel turn and caused the complete eradication of humankind - for the express purpose of making his brother suffer. It certainly worked, as King Thor now spends the millennia staring at a Midgard that no longer needs his protection.
Poor old King Thor can't even find refuge from the horrors of the future in his home on Asgard. An especially vicious villain from his past, Gorr the God Butcher, pops up again after humanity is annihilated and continues his violent campaign of deicide.
Gorr uses his trusty blade, All-Black the Necrosword, to thrash Thor once again, but he doesn't kill him - instead, he continues to slay or enslave all the other gods in the universe until the Odinson is the only one left. Now, King Thor is more alone than ever, firmly defeated and left with an Asgard overrun by Gorr's minions.
Gorr the (appropriately named) God Butcher kills most of Thor's fellow Asgardians, but he captures and enslaves a select trio of them - Thor's granddaughters, the Goddesses of Thunder. Gorr presses Frigg, Ellisiv, and Atli into duty alongside other imprisoned gods in the making of the sinister-sounding Godbomb.
Gorr intends the device to be the culmination of his lifelong campaign to rid the universe of deities by wiping out every god in existence throughout both space and time. In other words, it's one of the most powerful weapons the Marvel universe has ever seen.
Old King Thor may look diminished, but he's significantly more powerful than the modern version of the character. As the Allfather of Asgard, Thor inherited the Odin Force from his father and cleverly renamed it the Thor Force. King Thor has access to all of Odin's wondrous powers - and his gigantic Odinsword - but even that is not enough to defeat the God Butcher.
To be fair, the King of Asgard also has some significant weaknesses at this point in his life, including a missing left arm that he replaces with an appendage from the Destroyer.