The Cortex System is a generic RPG system based on the Sovereign Stone System, and was developed by Margaret Weis Productions, Ltd for the Serenity (role-playing game). It was subsequently used for their licensed Battlestar Galactica and Supernatural RPGs, and brought out as a stand-alone system in the Cortex System Role Playing Game book (also called the Cortex Classic System Role Playing Game). Serenity, using the Cortex System, was the 2005 Origins Award Gamer's Choice Role Playing Game of the Year.