Notes on the Last Theorem is a leather-bound journal written in Aklo by a careful hand. The book once belonged to the Chelish diplomat Necerion, a man who recently abandoned his duties in Magnimar and went missing. With a successful DC 15 Society check, a PC recalls rumors that Necerion traveled to Osirion to chase legends of hidden treasures in the desert sands.
If the PCs can read Aklo, they can learn the book’s contents after a few hours of skimming—otherwise, Keleri, who knows the language, can inform them of its contents. The book focuses on cataloging information about the supposed contents and location of a rare tome called The Last Theorem—a book said to contain exhaustive information on the sinister aliens of the Dominion of the Black, and in particular a number of hints toward an upcoming invasion of Golarion by these horrific monsters.
In addition, the book notes that The Last Theorem is said to contain magical formulas, equations, and incantations capable of affecting the physical world and “making ready the world for its new Dominion rulers.” Much of the book seems to be concerned with an upcoming doomsday, yet no clues in Notes on the Last Theorem indicate what date this doom is to occur.
The mysterious book also clarifies that Necerion was much more than merely a Chelish diplomat and irrefutably proves that Necerion had ties to a nefarious secret society of Dominion cultists known as the Night Heralds. The book doesn’t go into further details about the Night Heralds.
At this point, Keleri tells the PCs she has a secret to share—she is a member of a secret society whose interests lie in the hidden nature of reality: the Esoteric Order of the Palatine Eye. Among other goals, the Esoteric Order seeks to find and control dangerous lore and secrets so that cults like the Night Heralds cannot use them for ill intent. While the Esoteric Order has other primary enemies (such as the death cultists known as the Whispering Way), they have of recent years grown more and more concerned with the machinations of the Night Heralds, and the hints provided in the pages of Notes on the Last Theorem are truly worrying to Keleri, who fears that Necerion may be seeking some ancient doomsday weapon or other potent artifact. She cautions that the group is dangerous and must be stopped.