I know I'm probably reaching here, but my theory is that this alternate future version of Lex Luthor somehow managed to reverse-engineer Brainiac's Krptonian tech to use for his own nefarious purposes after Superman lost his powers.
It would explain why he has an army of Eradicators and the three dots on his head.
Guess this is the closest we're ever going to get to a Luthor and Brainiac team up in this continuity.

















