Lex Luthor has left no stone unturned in his quest for the Black Lantern energy, but he's not the only one searching for it - Brainiac wants the energy and the knowledge it offers all to himself. Trust us, this is gonna be the most vicious Luthor/Brainiac team-up ever. It all sets the stage for both a conclusion and a beginning in next month's historic ACTION COMICS #900, featuring the return of you-know-who…