Lex Luthor, who is portrayed by Michael Rosenbaum, was a series regular on Smallville from the first season until the seventh. Lex, of course, grows up to be Superman's infamous arch-nemesis.
Lex: Our story hasn't been written yet, Kal-El. And every villain is only as great as his hero. You see that all relies on you saving us from a coming Apokolips.