Crossover Earths are the oddity of any Multiverse as they are an amalgam of worlds owned by two separate companies. For the characters from two comic book publishers to team-up the writers usually have to resort to several common plot devices. One of these is to say that the characters actually live on the same Earth, but have only just met each other (e.g. JLA/The-99). These gestalt worlds are Crossover Earths, hybrids of two existing Earths (say the DC Earth and the Marvel Earth), which exist solely for the duration of the published team-up.
Major Constituent Universes
|Angor||The original Angor was created in the 1970s as thinly veiled parallel of the Marvel Universe created for an unofficial crossover with the Justice League. Those characters were later used by the 1980s JLI title for a cycle of stories which eventually led to the introduction of the robotic Extremists. This world was the inspiration for the post-Infinite Crisis Earth-8.|
|Earth-99 (JLA/The 99)||This is the setting of the crossover mini-series JLA/The-99 featuring DC Comics’s Justice League of America (Superman, Batman, and co) and Teshkeel Comics’ The Ninety-Nine (a group of Islam inspired teen superheroes).|