Of course, they were doomed. They did make an accounting of themselves before their revolution was thrown down, though. Ultimately they were defeated. Their punishment was to have their essence split. They were divided into humans, elves, dwarves, and orcs. Some of the First escaped the sentence, and bade their time, hidden from the gods.
Once the Lessers, as the First refer to the "split" races, had developed sufficiently the First came out of hiding. They very carefully assimilated themselves into Lesser society, albeit as overlords and rulers. They had carefully laid out boundaries for themselves, to prevent them gathering or coming into conflict, in order to not draw the gods' attention. They became known as the Mage-Lords.
The Mage-Lords bred, bred with, and otherwise manipulated the Lessers to create new races and/or modify the original Lessers to better fit their needs. They were ruthless and cruel, vengeance burning hot and bright in their hearts. Some descended into a madness the depth of which only godlings such as they could fathom. These became known as demons and devils.
The empires of the Mage-Lords were vast and powerful. The Mage-Lords possessed a command of magic and artifice the world has never known since. The states and provinces of their empires were interconnected by dimensional gateways and teleportation devices. Paired scrying mirrors were used for communication. Many of the greatest cities were connected by paved highways. Trade was facilitated by these paved roads, as well as by caravansary at regular intervals.
For generations the Mage-Lords were content to rule within their enclaves. Eventually, though, they turned ravenous eyes on their brethren. Their wars forever changed the world. They shared minor secrets of their magic and artifice, instructing certain talented Lessers. Some were deployed as battle mages. Some were imprisoned in magical smithies, slaves set to making magical artifacts of war.
For thousands of years these wars were waged. Eventually all of the Mage-Lords became embroiled in these conflicts. The gods were content to allow these wars to play out. They realized who the Mage-Lords were and watched as they killed each other off. Eventually, there was only one, called Zagrath. Swollen with pride, he believed that having killed all of the other Mage-Lords and assimilated their power, he was ready to vie against the gods.
He marshalled his forces and summoned great and terrible magic. He opened a gateway to the gods' realms and sallied forth. The struggle was titanic. Zagrath bested many of them before he fell. Eventually the gods, at first divided, came together and overcame the upstart. They visited every manner of suffering on him they could conceive. Finally, when they tired of their sport, they threw him down. Literally. Already broken and mad, he plummeted from unimaginable heights to crash into the world. What was left of his mind was lost in that unending fall, and what remained of his body was utterly ruined in his landing.
He landed on a peninsula extending from the southeastern shores of Calanthas, known as Fahldrag. He crashed into a mountain whose original name is lost to time. Now it is called Sloth Negaimus. It is widely believed that Zagrath lies there still, where he fell, a mad godling in a ruined body, plotting revenge and conquest.
There are whispered legends of lost prophesies that as Zagrath warred against his brethren, he kept them alive. He didn't merely assimilate their power. He kept them alive after a fashion, tapping into their living power. Some say that without Zagrath to hold them in thrall they will regenerate their former power and return to torment the world. Most of these legendary prophesies are scoffed at by sages and intellectuals as fabrications of charlatans and hustlers.
There is also the prophesy of Niamician. It is well-recorded and attributed, even if it isn't widely respected. No one knows exactly what Niamician saw in his prophetic vision, but it drove him irretrievably mad. His only writing of the prophecy was this:
"When Zagrath rises, dark and bloody,
clutch tightly your fear with one hand,
and weep your despair into the other."