Big Bad
Margot Kidder, who played Bridgette Crosby, was supposed to become the primary villain of season four. However after Christopher Reeve’s untimely death in 2004, the producers decided to incorporate his real-life death into the plot as Virgil Swann was killed off screen. Naturally Kidder was not pleased with this decision, as she felt the producers were just capitalizing on the actor’s passing. Therefore she backed out of her commitment. Genevieve Teague, played by Jane Seymour, was therefore created as big bad for the rest of season four.
Brainiac
Laura Vandervoort briefly portrayed Brainiac who posed as Kara in the series. In Supergirl, the new series, she portrays Indigo, a character who we know from the comics is later revealed to be Brainiac 8.