User blog comment:Doomlurker/After Arkham City/@comment-1629132-20111211073722/@comment-5254608-20120709010106

In one continuity (is that how you spell it?) there is/was already a so called "Arkham world" though never referred to as such... Every super powered villain is thrown there. So an Arkham World would already have a basis in the DC universe.

(I got this information from a third party source, my step father, who is/was an avid comic book collector/reader.)