Samantha Ann Mulder is a fictional character in the television series The X-Files. She is the younger sister of FBI Special Agent Fox Mulder and the daughter of Teena and Bill Mulder. As a child, Samantha was abducted, ostensibly by aliens, and was never returned. It is this experience that drives her older brother Fox Mulder to join the FBI, and later take the reins of the X-Files section.
Ashlyn Rose as Samantha Mulder in "Dreamland II"
Fox William Mulder is a fictional FBI Special Agent and the secondary protagonist of the Fox science fiction-supernatural television series The X-Files, played by David Duchovny. Mulder's peers dismiss his many theories on extraterrestrial or paranormal activity as those of a conspiracy theorist and supernaturalist; however, his skeptical but supportive partner, Special Agent Dana Scully, often finds them to be unexpectedly correct. He and Scully work in the X-Files office, concerned with unsolved FBI cases that are often revealed to be supernatural or extraterrestrial in nature. Mulder was a main character for the first seven seasons, but was limited to a recurring character for the following two seasons. He returns as a main character for the tenth and eleventh seasons.
Duchovny portrayed Mulder, the main character in the first seven seasons and the tenth season, as well as a recurring character in the eighth and ninth seasons.