The Fall

The Fall is the tale of the end of the glorious Diamond Age. The term itself can refer to several things that took place at that moment: The fall of humanity from grace, the destruction of the near-mythical flying city called New Aether, or the fall of Herobrine from the heavens as he rampaged against humanity’s unchecked cities.

Summary

Herobrine saw how humanity feared the dangerous world outside the caves they huddled in. He pleaded with his family to give him something to teach them to protect themselves.
Herobrine’s family, after much pleading, agreed, and Herobrine gave humanity the knowledge of how to craft tools, of how to mine, to farm, to fight. Humans graciously accepted these gifts and set out to strike back against the world that scared them so, and strike back they did.
Years passed. Forests gave way to sprawling cities as mountains were stripped to their routes for minerals. Monuments sprang up by the shore as temples were erected in deserts and jungles. Hogimal, Turavus, and Ses’ser looked upon humanity’s accomplishments and were pleased. They brought forth Yona, the goddess of love... Avalan, god of Redstone, and Celes, goddess of death.
But all good things must come to an end. Humanity saw how the gods were pleased and began to grow proud... so proud in fact, they felt they were gods themselves in their hubris. Their cities grew bigger, the earth more torn and scarred as the beasts which were once so feared were ground into even more resources.
Herobrine saw this, and grew first sad, then enraged. In his wrath, he tore down factories, crumbled cities, and unleashed a fury that shook and reshaped the earth.The other gods saw this, and captured their brother, locking him deep underground, but the damage was done. Civilization as humanity knew it was gone, and so humanity hid from the gods’ anger.
When they emerged, it was a changed world. The ruins of the former cities now held nothing but forgotten memories and groaning undead. Humanity had been given a second chance.

Historical Basis

While the Fall of Herobrine itself is regarded as fabrication, it IS known that at some point in time, humanity was forced into underground bunkers as a calamity ravaged the world, deactivating the network of portals between the Overworld and the Nether, and collapsing several End portals.
This event led to the beginning of the Gold age, which, despite the name, was in fact a dark age where humanity’s culture, demographics, and economy deteriorated to a pre-medieval status, where redstone technology was abandoned and lost, records of previous accomplishments were destroyed almost entirely.

Spread

This myth, with some variations due to drifting and retellings, is fairly common knowledge.

Cultural Reception

This myth is typically only found in human and Villager cultures, as due to the End and Nether being separate dimensions, they would have theoretically been wholly unaffected by Herobrine’s wrath. The only noticeable effects would have been the previously-mentioned deactivation of Nether Portals.