In much the same way that Superman and other heroes have evil analogs on a parallel world, Lex Luthor had a heroic counterpart there; who decides to adopt a heroic identity to combat the evil Crime Syndicate of America.
Taking inspiration from multiple versions, Alexander Luthor wears an armored suit similar to his Earth 2 Graphic Novel Appearance, but also wields Blue Kryptonite and incorporates gold in his suit similar to the Crisis on 2 Earths Animated feature.
