sentences:  During the 2007 Comic Con, it was revealed that Dean Cain, who played Clark Kent/Superman in "", would have a guest role as a "the evil Dr. Curtis Knox" in the fourth episode "Cure".Marc McClure, who portrayed Jimmy Olsen in all of the "Superman" films as well as in "Supergirl", was brought in to play a Kryptonian scientist named Dax-Ur for the episode "Persona".James Marsters was brought back to reprise his role as Milton Fine/Brainiac in a four-episode arc slated for January 2008; Marsters had not appeared on the show since the season five finale "Vessel".