A probe exploring the chlorine-rich atmosphere of the world Doreen
The chlorine world biosphere of Doreen (Omicron Afri II, beyond the Butterfly Cluster) generated a sapient species about four million years ago. Archaeological research by scientists from the Sagittarius Cooperation has shown that this species developed a technological civilization, achieved interplanetary travel, and created artificially intelligent machines. This set of advanced cultures then apparently destroyed itself in a system-wide war or series of wars that involved a nuclear exchange and germ warfare on the home planet, cometary bombardment of targets throughout the system, and an ecological and economic collapse so profound that the entire species became extinct.
According to the evidence the Doreens (so named after their planet, since their own name for themselves is unknown) were heavy users of fission-based nuclear power, partly because of the relative abundance of such materials on their world, and they drew very heavily on the massive coal-like deposits typical of chlorine worlds as well. This abundance of energy was likely a factor in their swift transition to Interplanetary level technologies once civilization arose. Reconstructions show that they were quite large, triradially symmetrical (quite unusual in a motile species) and individually of superbright intelligence. The remains of numerous and extensive military installations suggest that the most aggressive of their cultures were predominant. The biosphere that generated the Doreens was severely damaged, not only by the final wars but also by extensive resource exploitation in the preceding centuries. It is not expected to recover for some millions of years yet. There are life forms comparable to arthropods, but all larger and more complex forms of animal life are believed to be extinct. There are many ruins but no working mechanical installations or bot life on the planet itself.
The Doreens had begun intensive exploitation of their entire star system's resources at the time of their demise and in the process had established a number of insystem colonies and space habitats. They also appear to have been engaged in the production of generation ships shortly before the wars broke out. Whether any of these ships were ever launched — and if so where they might be now — is unknown. Just as on the home planet, all records in the abandoned habs about the system seem to have been destroyed or erased, and there are no functional bots or other machines at those sites.
The Doreen system was not entirely uninhabited when it was first discovered. The surviving mechosystem underwent subsequent development and is dominated by a single being, apparently of S:1 level. This being is extremely hostile toward all other life forms, particularly bionts. Early attempts on the part of researchers from the Sagittarius Cooperation to engage the Doreen transapient in dialogue met with failure. There has since been some limited contact between this transapient and the Caretaker Gods, but the results were disappointing to outsiders. In the end, entry to the system was forbidden to S<1 entities other than those operating under the close supervision of a transapient representative of the Caretakers. Several groups have expressed interest in attempting to lazurogene the original Doreen bionts, but if it is available at all the necessary information for an authentic restoration is under embargo.
Some believe on the basis of available evidence that the Doreen transapient precipitated the final wars in the Doreen system.