The 97th Cosmos is a parallel universe where the Earth was home to only one sapient species, Mankind. In 1897, the Wellsians, native to the neighbouring planet Mars, attempted an invasion of Earth, foiled when the Wellsians proved sensitive to human diseases and were almost completely wiped out by a flu outbreak. These events bore an eerie similarity to War of the Worlds, a work of fiction in the Prime Universe.
Decades after the near-complete destruction of the Wellsian Empire, the 97th Cosmos was one of the universes where the Crew of the Copper-Colored Cupids decided to construct a base. Located on Venus, Morningstar 1 was the location of a crisis in 2019 when the alchemist Mandragora-257 dug up some Wellsians who had crashed there a century earlier and attempted to revive them. This eventually led to the destruction of the base and to the five surviving Wellsians acquiring a Fog Ship, escaping out of their home universe and into the wider multiverse.
Behind the scenes
The 97th Cosmos was first seen in 2019 in The Wellsians.
It presumably derives its name from being defined primarily as a universe in which the events of H.G. Wells's War of the Worlds truly happened, the novel having been first serialised in 1897 (also the date mentioned in The Resurrection of the Wellsians for the in-universe Wellsian invasion of Earth). Likewise, the “HG” in Earth-HG66 is a transparent enough allusion to H.G. Wells's initials.