Prime Universe
According to Sylvester Shoebill, the Prime Universe was so named because “[its] representative was first in line at the registration office when the Council of Frogs put together their little Doomsday Book”.
It included a version of the Earth, inhabited by a number of coexisting sapient species, including humans as well as anthropomorphic shoebills. (PROSE: The Grand Multiverse Hotel) Its Victorian London was home to Sherlock Holmes and his associates, as well as to Sexton Blake. (PROSE: The Time of the Toymaker) In 1960, a scientist from the Prime Universe invented the Clockwork Cherubs, who, in the form of the Crew of the Copper-Colored Cupids, later relocated to a pocket universe of their own, the Cupid Homeworld. (PROSE: The Grand Multiverse Hotel)
A version of Atlantis existed on the Prime Earth in ancient times, and was believed to have possessed advanced technology. In the 20th century, a malevolent organisation called the First Horde sought to rediscover the ruins of Atlantis and use its technological secrets to take over the world. The Strangely-Colored Secret Societies came into existence as offshoots of the First Horde. (PROSE: The Strangely-Colored Secret Societies)