The Ordo Chronos are one of the smaller Ordo Minoris of the Inquisition, and it is thought that they studied the passage of time when traveling trough the warp. Few amongst the Ordo Calixis have heard of the Ordo, and even fewer possess any real knowledge as to their true purpose.
It is thought that their Ordo was established to study the anomalous passage of time during interstellar travel through the warp. This is because of the fact that time works differently within the empyrean; vessels undertaking a journey taking months can in rare circumstance emerge to discover that centuries have passed within the mortal realm, despite the intentions of the vessel's Navigator. Such dreadful tales are common knowledge amongst void travellers and accepted as one of the risks of warp travel. Even rarer within the Imperium are tales of Human vessels entering the warp, only to emerge at an earlier point in history.
As a result, this Ordo is believed to have been established to study the temporal anomalies or other such effects that might emerge within the vicinity of the Jericho Reach with a view to controlling or combating them. Inquisitors of the Ordo Chronos were particularly concerned with the effects of time distortions which could lead to a disruption of the proper flow of time due to unintended interventions in the past. Such actions are deemed as interference in the fate of Mankind and against the will of the God-Emperor. Over the course of centuries, the Ordo Chronos expanded their mandate to relate to all forms of temporal phenomena and include other such events that might be a deliberate attempt to interfere with the flow of time.
However, following this chain of events, the Ordo Chronos has seemingly disappeared, and all its members have vanished. Their true fate remains unknown, with some believing that they are in hiding whilst others hold the view that they came into competition with renegade factions of the Adeptus Mechanicus in the pursuit of long forbidden technology. Regardless, the fate of the Ordo Chronos remains a mystery to those few that know of their existence, and some wonder whether they will emerge once more in the future.