The Chronomasticon was the manual of Triphis' ship. It resembled a glass ball filled with swirling colours. A small portion of the Chronomasticon catalogued unstable touch-points between different histories and intersections between laws of reality, creating a map of points in space-time which could be used to accurately create any imaginable version of history.
During the War in Heaven, Triphis made Tefen play with the Chronomasticon with her, creating new versions of Earth's history in which it was taken over by aliens. In the process of using the Chronomasticon, Tefen began fusing with it. (PROSE: Playing for Time)