Fall of D'ni
The Fall of D'ni, often simply "the Fall", refers to the Leesahn 8, 9400 DE attack on D'ni by Veovis and A'gaeris, who used an unknown biochemical agent to kill most of the empire's population.
Timeline
A'gaeris's expulsion
Fifty years before the Fall, A'gaeris was expelled from the Guild of Writers over the theft of a Descriptive Book, a crime he vehemently denied committing. He moved to one of the lower districts in the city, writing subversive pamphlets and gaining a following of lower-class citizens.
Anna's arrival
When Anna ventured from the surface down into D'ni, her arrival was cause for concern among many of the more insular-minded D'ni. Her friendship with — and eventual marriage to — Aitrus, along with the birth of their son Gehn caused even greater tremors in D'ni society. Their marriage ultimately broke the friendship between Aitrus and Veovis. Anna brought with her a fresh perspective on the workings of D'ni, and urged Aitrus to use his position on the Guild Council to introduce a proposal to improve the conditions for the lower classes of D'ni society. When the proposal narrowly passed over Veovis's strong objections, his friend Suahrnir suggested talking with A'gaeris about what might be done to counter it.
A'gaeris manipulates Veovis
Shortly after the passage of Anna and Aitrus's proposal, two apprentice guildsmen in the Guild of Maintainers went missing under suspicious circumstances. Many of the guild masters in the other guilds participated in a massive search of the Ages to find them. Among them was Aitrus, who was assigned to search the Ages belonging to Veovis's family. Angry that Aitrus seemed to constantly be getting involved in his affairs, Veovis eventually sought out A'gaeris to talk. A'gaeris, in turn, used his meetings with Veovis and his own skill at handwriting forgery to convince the young lord that Aitrus was writing illicit Ages, a serious crime. At the same time, he used his interactions with Veovis to convince Aitrus that his former friend was selling Ages on the black market. As a final piece of evidence, he gave Aitrus a Book where the two apprentice guildsmen were found murdered with Veovis's dagger.
Veovis was arrested, convicted of murder, and sentenced to life in a Prison Age. With the aide of Suahrnir and A'gaeris, however, he managed to escape his prison and went into hiding on another Age.
Terrorist attacks
A'gaeris used the false conviction of Veovis that he had orchestrated as a means of ensuring the young lord's help in taking revenge on D'ni. They used their skills at Writing, along with Suahrnir's access as a member of the Guild of Maintainers, to execute targeted assaults on key Council members and D'ni infrastructure. Guild masters were mugged; the Guild of Ink-Makers' Ink-Works was bombed; and one of the five great classics was desecrated. Veovis was eventually recaptured and sentenced to death, only to have Anna plead for his life. Moved by her words, the five Lords of the Guild Council agreed to send Veovis to a new Prison Age, and the Book burned immediately afterward to preclude the chance of rescue.
Out of concern that his uncaught co-conspirators would be able to rescue him, the Book was crafted in secret by multiple Writers, and Veovis sent through the link in a secret chamber. Yet Suahrnir, whose involvement in the attacks was still unknown, was able to provide A'gaeris with a Linking Book to the sentencing chamber. The time that Veovis's sentence was due to be carried out was public knowledge, and A'gaeris used this to his advantage. Once Veovis was sent to the Prison Age, A'gaeris used the Linking Book that Suahrnir provided to link into the sentencing chamber, his hand positioned such that he immediately followed Veovis into the Prison Age with a way out. The Council members in attendance, none the wiser to what had happened, proceeded to burn the Book as planned.
Final revolt of Veovis
On Leesahn 8, 9400 DE, Veovis and A'gaeris executed their final attack on D'ni. Using some form of explosive charge, the pair split open a hole in the cavern wall, unleashing an unknown, gaseous biochemical agent into the D'ni cavern. The gas filled the cavern and quickly killed most of the lake's bio-luminescent algae; most D'ni took between hours and days to succumb. Not content with killing those who lived in the cavern, A'gaeris and Veovis used the bodies of the deceased to transmit the agent to the numerous D'ni homes and settlements in other Ages, killing many of the cavern's refugees.
Aftermath
As a result of the attack, most of the D'ni people perished, and a great deal of structural damage was done to nearly every part of the cavern. Roughly 80 years after the Fall, expeditions led by Atrus and his companions uncovered nearly 2,000 survivors in various Ages. Together, they began the First Restoration, but ultimately chose to relocate to a new Age, Releeshahn, instead.
