Turned out that not-Batman is a repressed homosexual who wants to (and successfully does) take over the world. This isn't far off from various versions of Batman, but he also kinda employs Luthor's strategy from Kingdom Come of brainwashing a boy-with-magic-word-access-to-god-power, in this case making him not-Robin who likes and yet kills not-Flash...
Oh, and there might be an impending invasion from outer space as a sort of impetus for uniting the world. So a bit of Watchmen in there, too.