I'm calling horse crap. Literally all the villains are Batman Characters...before and one goes DUR, LEX LUGOR I MEAN LUTHOR IS A SUPERMAN VILLIAN DUR! He featured as a very prominent character in the Batman universe as well. Though you basically only see the business man side of lex.
"No news, no calls, no tyranny until tomorrow!"- King K. Rool, 29 December, 1998