Katie Cassidy, Gina Holden, Callum Keith Rennie, Jim Beaver, Amber Borycki, Chris Gauthier, Ben Cotton, Sean Rogerson, Dean Wray, Jay Brazeau, Aaron Pearl,Alex Ferris, Maxine Miller, Anna Mae Routledge, Sarah-Jane Redmond, and Sarah Smyth have all appeared in episodes of Supernatural (2005), though not at the same time with the exception of Gina Holden and Callum Keith Rennie who were both in "Wendigo." Also Jim Beaver and Katie Cassidy were in a few episodes together.
Co-executive producer Dan Shotz stated that finding someone for the role of Abby Mills was the most difficult part of casting, with hundreds of actresses auditioning. Elaine Cassidy was found after her self made audition tape was sent from London to Los Angeles, four days before filming on the pilot presentation began.
Gina Holden (Shea Allen), David Lewis (Richard Allen), and Chris Gauthier (Malcolm Ross) star in The Butterfly Effect 2. A photo of Callum Keith Rennie (John Wakefield) is also featured, from The Butterfly Effect.
None of the main cast (other than Harry Hamlin who had signed on for only one episode) knew if their character was going to survive to the end of any episode until the day before they got the script. Rather than letting them read about it in the script the job of telling an actor that his or her character was going to be killed in the next episode fell to the Executive Producer Karim Zreik, a job that earned him the nick name "The Assassin".