Sakvaback (also pronounced Sökvabäck) was first colonised by the Scarlen Host in 5804 AT; they rapidly terraformed this cold planet using orbiting mirrors and swarmtech, but became isolationist and transcended in 6910 AT, leaving the planet uninhabited for over a hundred standard years. Most of the transcended entities migrated outsystem to the cold gas giant Geifon, where they have built vast processing arrays submerged in the the deep liquid water layer.
Unattended, the self-repairing mirror system continued to keep the planet moderately warm during the period, although some regions became colder due to the absence of the Host's processing and industrial activity.
The empty world became a goal for transcension chasers for a period, but was mostly empty of transapientech by 7013 AT when a second wave of permanent colonists arrived from the Regor Plexus. The new residents, mostly human-and mammal-derived clades, built their habitations in the warmer equatorial regions, and at first rarely ventured into the frozen icemires in the north and southern latitudes. Icemires, engineered ecosystems which use organically-produced antifreezing chemicals to reduce freezing in groundwater, need very little environmental management and generally have very low population density.
A few hardy colonists elected to make their homes in the colder regions of this world, and soon began to report unusual phenomena in the icy wastes. Uncanny patterns could sometimes be seen in the sky, or in the air above the ground, and strange figures, seemingly from bygone ages, were glimpsed moving through the tundra. Intangible and translucent, these figures seemed to take the form of people from the distant past and distant worlds; from the pre-spaceflight eras of Old Earth, to the colonies of the ancient First Federation, and even warriors from the Consolidation Wars were sighted, and recorded by sensor equipment, for short periods.
In due course these phantoms were determined to be the product of an immersive entertainment system devised by the long-departed Scarlen Host, consisting of historical fiction virch scenarios of various kinds, populated by charactersims of various levels of sophistication. From the few records that remained it appeared that many members of the Host had been obsessed with such fictions. The fashion for such virches had been short-lived, but coincided with the period immediately before the mass transcension of the earlier civilisation on this world.
For reasons that are unclear, a small number of these charactersims became independently sentient during the transcension, and continued to exist (as swarmghosts) in a hitherto-unknown form of hyperfog peculiar to this planet. The entities in the fog were often convinced that they still existed within the era of their fictional lifetime, and were generally very disconcerted whenever it became possible to make meaningful contact with them. Some of these beings had the simulated memories of humans from before the Industrial Age, or from the earliest eras of human spaceflight; suddenly they found themselves in a distant and unfamiliar future.
Even in the Current Era a few uncontacted swarmghosts can be found lurking in the thinly-spread hyperfog that collects above the icemires of Sakvaback; specialists in virch egress anxiety disorder are always available on hand to help the sims make the transition into modern civilisation.
The transapients dwelling in the warm ices of Geifon were uncommunicative for more than two thousand years, but emerged in the 9500's having spent this period developing new modes of interaction and systematic ethics. The Geifonians have introduced many valuable new cognitive behaviours into the Sakvaback culture, and Sakvaback has benefited from a major economic boost from this input, becoming one of the most influential worlds in the local plexus.