History

This Earth-789 is an amalgam of the Donnerverse and the Burtonverse. Its numerical designation denotes the years of the duo’s first solo movies: 1978 (Superman), and 1989 (Batman). Even the Supergirl movie (1984) is counted in it.

Trivia

Superman, Supergirl, and Batman are the only heroes in this amalgamated world.

Jack Napier an associate of Joe Chill mugged the Waynes and killed them. Later Napier became the Joker and Chill’s whereabouts are unknown.

Reeve’s Superman, Slater’s Supergirl, Keaton’s Batman.

https://dc.fandom.com/wiki/Earth_789?so=search

https://en.wikipedia.org/wiki/List_of_DC_Multiverse_worlds

Ref: Dark Crisis: Big Bang

^{Pic Credits: DC Comics}