"Show me a hero and I'll write you a tragedy."
After the eruption of Death Mountain and the arrival of the World-Eater, the tide of war shifted. I knew from conjured visions that Ganon was seeking pieces of the Triforce, but he expected our scrying and blocked our efforts. What began as frustration at Link's absence became desperation. The most adept mages of Hyrule, Lorule, and the Twilight Realm worked to seek out Link and summon him to our aid.
Ganon razed Lorule, and sought to destroy my realm as well. His armies attacked my kingdom, but I sealed the Mirror of Twilight, trapping some of his minions within my damaged realm, including corrupted souls of the dragons Faron, Eldin, and Lanayru. The Twilight Realm became a prison of evil. I despised this choice, but told myself it was necessary. Better for the dragons to be trapped here than laying waste to Hyrule.
As Ganon grew more powerful, as the World-Eater consumed more of Hyrule, as the skies darkened and the air grew bitter cold, the mages grew more desperate and frantic. In their desperation, the mages repeated spells with growing magnitude. Their efforts opened a rift in space and time, connecting all of Hyrule's history. Through this ever-changing rift, countless versions of Link, the Hero Chosen by the Goddesses, entered Hyrule. Each incarnation represented a facet of Hyrule's history, and carried equipment from those eras past or yet to be. Every incarnation was plucked at their prime: after they had accomplished the goals of their own quests. Over the course of several weeks, every incarnation tried to defeat the World-Eater, some alone, some in teams, others in armies.
Every incarnation failed.
As the final incarnation of the Hero fell, a blinding light and a searing heat filled the air. The Triforce had been shattered, and Hyrule was cleansed.
According to Midna, the Battle of a Thousand Heroes took place over the course of several weeks after a single portal was created. The Battle is occasionally misrepresented in other pieces of lore as a collaboration of every possible incarnation of Link combining their efforts to defeat Alduin.
Midna mentions that "every incarnation tried to defeat the World-Eater," which may seem to imply that the Hero of Time was present at the Battle of a Thousand Heroes. This was not the case, as the Hero of Time was trapped in Termina during the Last Great War of Hyrule. Midna mentions the Hero of Time at the beginning of the book, but does not indicate whether he was present at the battle. The context of "every incarnation," (i.e., following after Midna mentions that "Each incarnation represented a facet of Hyrule's history,") may indicate that she is referring to the incarnations summoned by Hylian mages, not necessarily every possible incarnation of Link.
Background and Inspiration Edit
The book was included in version 6.3 to provide an in-game explanation for the presence of equipment used by each Link of each Legend of Zelda game and to emphasize the finality of Hyrule's demise, and to solidify the destiny of the Dragonborn.