The Living Book of Eschaton was the end result of Ezekial's attempt at Dion de Vermiis' Eschaton Experiment. Gathering together the Ashtani and Theran cabals, Ezekial led the group in a large occultic ceremony, binding the karma of all its members together to facilitate its gather and usage. Unfortunately, something went wrong, and both Ezekial and the experiment were lost.
Eventually, the modern day Occultists successfully enacted a ritual to retrieve both Ezekial and an unfinished Eschaton from the timestream and finished the experiment, tying their karma to that of their forebears and creating a living book in, as its name suggests, the shape of a tome that could absorb and distil karma upon those tied to it.
In the year 691 AF the Eschaton was used as bait by the Occultists to lead a phoenix released by the Warlocks into the Chaos Plane to assault the hordes of Golgotha. The occultic legacy then was lost to public record, apparently consumed by the firebird.
The living book was later secretly recovered by the Ashtani, though heavily damaged. Its repair was effected with another temporal ritual in 870 AF, its working drawing the ire of the Genesis. Bain'maal was dispatched to punish Ashtan for the regression of time, though an emergency summoning of the Spawn of the Unnamable Horror combated his advance temporarily. The Second Great Work was completed successfully, enlivening a librum which now not only functioned as karmic reservoir and planar link, but also eldritch teacher of the apocalyptic arts of the Unnamable warriors.