The Monan Host attended a meeting of the Temporal Powers and were somewhat hostile towards the Time Lords. In the incident that followed, the Monans, among the other Temporal Powers, faced a brief but devastating invasion of their homeworld by the Daleks which decimated their population. Lady President Romana II of Gallifrey promised to provide aid in the rebuilding of the fellow Powers. (AUDIO: The Apocalypse Element)
The Monans generated an occlusion field to prevent other temporal powers from peering into their history. However, the Nekkistani managed to learn that an incident caused time and space to buckle around the Monan homeworld. This put the planet in contact with itself in ten different historical periods. This resulted in the most advanced Monans conquering their ancestors whereupon they studied and harnessed the time fields which allowed them to stabilise the ten planets into a single host system. (AUDIO: Square One)
- It was implied that they were allies of the Andromedans.
The Monan Host was one of the Temporal Powers. When their ship Moros was at the point closest to Gallifrey, it became infected with a computer virus that caused it to kill its crew and begin to collapse into a singularity. Romana II went on a mission to stop the core collapse. Originally, she regenerated in order to obtain the energy to stop the collapse; however, during the war that began after the Omega incident, Romana III sent Irving Braxiatel back to stop Romana II from regenerating on the Moros. As a result, the core collapsed and became a black hole.
The Monan Host, believing that the Time Lords had planted the virus, evacuated their embassy in the Capitol. Thirty minutes before the last representative left, Narvin was mysteriously murdered in the Matrix archives, causing many to suspect that the Monans had killed him. This fear escalated when the Monan embassy exploded and killed over a thousand Time Lords who had gathered for the inauguration of President Livia. In response, Livia formed an alliance with the Warpsmiths of Phaidon and declared war against the Monan Host.
However, the virus and terrorist attack were later revealed to have been part of a plot by Livia's Castellan Plutus and the Warpsmiths Kalbez and Gaal. Later, Romana II and Leela again changed the fate of the Moros by dying and stopping the core from collapsing. (AUDIO: Enemy Lines)
The Monans were exterminated by the Daleks at the onset of the Last Great Time War, which, along with the extermination of the Nekkistani, Sunari and Phaidonians, led to Gallifrey formally declaring war against the Daleks. (AUDIO: Desperate Measures)
In another alternate universe, the Monan Host were hunted down to near extinction by the Valeyard due to their time-sensitive nature. The last Monan was held captive in Chronopolis. (AUDIO: He Jests at Scars...)
The Host's temporal technology was, in some areas, even better than that of the Time Lords, though they never managed to achieve dimensional transcendence. It was known that they possessed a form of timeship, though all attempts at replicating their technology had failed. (AUDIO: Square One) The timeship that the Monan Host brought to Archetryx resembled a grey box. Its engines were powerful enough to cause a slipstream of temporal disturbance on its own. (AUDIO: The Apocalypse Element)