"I'm guessing there's more that I don't know about?"
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"I won't spoil the conclusion if you're eager to see this through."
This article contains MAJOR SPOILERS relating to
some of the most pivotal parts of Worm. Although all articles contain spoilers, this article will reveal major plot twists and should almost certainly be avoided unless you have finished the story.
Gold Morning refers to Scion's attack on various alternate Earths after being convinced to do so by Jack Slash. Over the course of four days, his rampage resulted in the deaths of tens of billions of people, possibly far more, before Scion was finally killed.
Trapped in Gray Boy's time loop, Jack Slash talks to Scion, persuading him to revert to violence instead of helping people.
Experimenting, Scion obliterates Great Britain on Earth Bet and discovers that the act makes him feel satisfied. 
With a new sense of purpose, Scion continues his rampage and moves on to Eastern Seaboard of the United States and Canada, killing tens of millions in a strafing run.
In his obliteration Scion followed a very specific pattern of reversing the way he had helped people in the past. 
Following his Eastern Seaboard attack he targeted all adults on the coast of Africa, leaving behind 430 000 orphans. 
In Russia he began trapping groups of people in a ring of fire that slowly burned inward.
Within a few hours, the total estimated death toll from his rampage went up to 500 million.
Immediately following the attacks, parahuman forces organized to minimize the damage and provide civilian evacuation out of Earth Bet.
The first meeting to discuss the situation between various parahuman factions was organized by Cauldron in a similar fashion to the Khonsu Meeting.
The meetings served to inform everyone present of the Scion's actions, organize preparations for evacuation and provide a discussion forum for possibilities of stopping Scion. 
At the meeting, it was decided to release parahumans from the birdcage, because they needed more powerful parahumans.
The first, and most notable, battle was the oil-rig battle. Afterward, roughly half of all the civilians and parahumans on Earth Bet were dead, and Scion began attacking other worlds as well.
Scion discovered the Cauldron Compound containing his comatose, gutted partner and destroyed it, ending his former partners' life.
The Final Battle
Scion was eventually defeated by thousands of capes under the command of Khepri, with the conflict shattering several landmasses on multiple worlds and rendering several uninhabitable.
Parahumans who fought in Gold Morning wear a yellow insignia, a golden circle with a gold dot inside, the alchemist symbol for gold, to show that they were there.
The name 'Gold Morning' was mentioned once in the final chapter of Worm, and has been adopted to describe the entire event, especially in Ward.
Number Four estimated that around 52 hundreds parahumans were brought into the conflict, around 18 hundreds died, mostly after Doormaker's exhaustion.
↑ 1.01.1 What I don’t understand, is why a blank slate like you would default to doing good deeds, rescuing cats from trees. Why not turn to that violence, as our ancestors did? It drove them, just like it drives the basest and most monstrous of our kind. - Jack's words Excerpt from Interlude 26
↑ The simulated human mind within the entity felt a glimmer of something at that. Pleasure? Relief? Satisfaction? - Excerpt from Interlude 26
↑“United Kingdom, first target struck. Obliteration,” the Doctor said. “Eastern coast of Canada and the United States, damaged, but casualties were a third of what they were in the initial strike.” -
Excerpt from Extinction 27.2
↑“(He's) Following a very distinct formula. He’s reversing what he did at the outset. Saving children, stopping fires. The man who initially gave him the orders is hospitalized, or we’d ask about the instructions he provided. It might give us an idea of what Scion is going to do and the patterns that might emerge in the course of this… experimentation.” Doctor Mother Excerpt from Extinction 27.2
↑“In Russia, his beam started fires. He cut off every escape route, then began setting fires from the outside in. It took him thirty-five minutes to start the fire, and he waited for fifteen minutes while the flames spread and everyone within was cooked. Heroes that attempted to stop the attack were killed.”Excerpt from Extinction 27.2
“We lost just about half of everyone,” Tattletale said. “Maybe more, but communicating’s hard right now. Don’t exactly have an infrastructure.”
“The capes, the civilians. Everyone. Half of Bet’s onetime population is gone, just about. Good news is he’s traveling between possible Earths, hitting major population centers, so the individual incidents aren’t doing so much damage on a relative level. Bad news is he’s traveling between possible Earths.” - Excerpt from Cockroaches 28.1
↑“I don’t want to sound negative, but, um, I guess I’m going to sound negative. There are people in third world countries who might disagree, and victims of Gold Morning.” - Excerpt from Interlude: End
↑Five thousand, two hundred and twelve parahumans had attended the final confrontation against Scion. Two-thirds of them had survived, with the majority of the losses occurring in the period after Doormaker had shut down, but before Khepri had achieved strategic control. - Excerpt from Interlude 14.z II