After The Incredible Hercules and a couple of miniseries featuring Amadeus Cho ran its course, the plot threads left hanging were finally resolved in this Crossover event.
The Japanese evil god Amatsu-Mikaboshi, who got a hold on many enslaved alien gods during Secret Invasion, goes on a rampage across the universe intending to destroy the entire creation and return everything to primordial chaos. Unlike Annihilus however, he takes out gods and other supernatural entities first. Hercules, who has just come back from his supposed death with a significant power boost, assembles a team of gods and close enough individuals to combat the king of chaos.
Chaos War contains examples of:
- And I Must Scream: Ares got turned into Chaos King's puppet and sent to murder his son while staying conscious.
- The Anti-God: Chaos King is described by Eternity in these very terms. His goal is to 'unmake' all existence.
- Apathetic Citizens: Hercules comes back from the dead to announce the death of the universe, but who cares? Is it that part of the month again?
- Backup from Otherworld: Since the various death gods were obliterated, a number of dead heroes got back in the land of living, which came rather handy with most living people being put in coma.
- Big Bad: Amatsu-Mikaboshi, the Chaos King.
- Deus Exit Machina: Eternity appears but refuses to fight Chaos King because he can't exist without him even though his victory means Eternity will cease to exist.
- Do Androids Dream?: The Vision is one of the Avengers temporarily brought Back from the Dead, suggesting he is actually a living being. This contradicts The Thanos Imperative, where a parallel universe Vision was immune to posession by Eldritch Abominations specifically because as a synthezoid he was never really alive to begin with.
- Does Not Know His Own Strength: Hercules trying to give a heads up on the end times is stymied by inexperience with his recent omnipotence. His cries are quite literally explosively thunderous and his steps earthquaking.
- Earth Is the Center of the Universe: Near the climax Gaea explains that she was the first being to emerge from primordial chaos. Earth is the final battleground of the Chaos War and it's where Amatsu-Mikaboshi, who is a counterpart to Eternity itself, was imprisoned.
- Eldritch Abomination: Amatsu-Mikaboshi is revealed to be an entity of living darkness predating the universe itself, and seeks to return it to the void by devouring everything in existence.
- The End Is Nigh: Hercules suddenly appears in New York, claiming that the end is coming.
- Evil Versus Oblivion: Mikaboshi wants to destroy everything and that includes evil entities like Nightmare and Satan.
- Generic Doomsday Villain: Chaos wants to destroy all the multiverse, just for the heck of it.
- Killed Off for Real: Athena by Hercules, in defiance of her request that he continue to be Top God.
- Nice Job Breaking It, Hero!: Hercules reveals the Godheads' whereabouts to force them fight back against Mikaboshi instead of hiding. Mikaboshi simply slaughters them and their realms, adding to his already immense power.
- Pocket Dimension: A provisional solution was to move most people on Earth to one of those. Amadeus did not like to play God and decide who lives and who dies. Eventually, he found another solution: put the Chaos god, at full power, in this dimension, where he believes he did win... while the majority of the multiverse has a reset that brings back those he killed.
- Reset Button: At the end Hercules used his super-god powers to restore the almost entirely destroyed universe, bringing several characters Back from the Dead while he was at it.
- Right for the Wrong Reasons: Played with. In the flashback of his first moment after being created, Vision discussed with Ultron about Rene Descartes. Vision said that he was incorrect, because an imperfect being (Henry Pym) created a perfect one (Ultron). Ultron was infuriated by his answer: yes, Rene Descartes was wrong, right, but not because of that. Descartes was incorrect because he was human! Ultron is not, and he generates his own logic! But, as both of them were taking deductions from Ultron's Insane Troll Logic premise (he's not perfect), then none of them were actually right.
- Rousing Speech: At first subverted, with heroes being of not very high opinion about Hercules, but played straight soon after.
- Seen It All: Iron Man is not surprised at all to see Hercules resurrected. That's a common tradition in the superhero community.
- Too Dumb to Live: Hercules has been granted omniscience, along with omnipotence, which would allow him to know before hand if a plan is going to work or the proper course of action to win. He never uses it which causes him to make one mistake after another including letting Mikaboshi into heaven by the front door. He also inisist on punching Mikaboshi even after it doesn't work. It takes getting his butt kicked, his hyper-smart friend Amadeus Cho, Gaea, and finally an attempt at consulting his omniscience to make him consider trying something else. Except he goes back to trying to punch Mikaboshi and is losing until Cho tricks Mikaboshi into another universe. Some god of gods.
- Took a Level in Badass: Both Hercules and Amatsu-Mikaboshi. Since they were Physical Gods to begin with, Hercules obtains Skyfather levels of power while Amatsu-Mikaboshi reveals his true form as an Eldritch Abomination.
- Unusually Uninteresting Sight: Hercules comes back from the dead, but nobody finds it surprising or stare at him in disbelief. See Apathetic Citizens and Seen It All.