Cypher ~ The Unbound
Just like the Earth you know and love, but populated by a race of bird-like humanoids, called Avvans instead of humans. Also birds are replaced with winged mammalian monotremes the Avvans call bats. And bats, likewise, are replaced by birds. Except penguins, they're still the same for some reason.
The home of Dr. Edgar Islington, Clyde Moreau and Isadora Islington.