List of The X-Files characters

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The X Files is an American science fiction television series first broadcast in September 1993 and followed by two feature films: The X Files and The X Files: I Want to Believe. The characters defined the overarching mythology of the series. They appeared in a range of episodes across several seasons.

The first seven seasons of The X Files star Gillian Anderson as Dana Scully, a medical doctor and hard line scientist assigned to work alongside Fox Mulder (David Duchovny), an esteemed FBI profiler who left his coveted position to head up a unit that investigates the paranormal and the unexplained. Tasked with debunking Mulder's work, Scully eventually comes to question her own faith, while Mulder continues to search through the archives of the Hoover building in order to find out what happened to his missing sister. The first seven seasons feature recurring appearances by Walter Skinner (Mitch Pileggi), conspiracy theorists The Lone Gunmen (Tom Braidwood, Dean Haglund, and Bruce Harwood), and secretive informants Deep Throat (The X Files) (Jerry Hardin) and X (The X Files) (Steven Williams). The eighth season and the ninth season represent a change in the direction of the show: Duchovny departs the regular cast and thereafter takes the role of intermittent lead. Scully, now a reluctant believer, is partnered with Special Agent John Doggett (Robert Patrick), a former NYPD detective and a strict skeptic who is still grief stricken over the death of his son, Luke. As Doggett begins to work on the X files, Scully continues her search for Mulder, while also carrying his child. At the end of the eighth season, Scully departs the X files, accept a teaching position at the FBI Academy. Thereafter she acts as only a consultant to Doggett. Annabeth Gish (as Monica Reyes), and Pileggi (as Skinner), join the main cast during the ninth season after recurring previously. The tenth season once again stars Duchovny, Anderson, and Pileggi, while Patrick is notably absent. Gish guest stars in the finale as Reyes.

Character Portrayed by Seasons 1 2 3 4 5 6 7 8 9 10 11 Cigarette Smoking Man William B. Davis colspan="3" colspan="4" colspan="2" Alex Krycek Nicholas Lea colspan="2" colspan="5" colspan="2" Jeffrey Spender Chris Owens colspan="4" colspan="2" Alvin Kersh James Pickens, Jr. colspan="5"

Character Portrayed by Seasons 1 2 3 4 5 6 7 8 9 10 11 Deep Throat Jerry Hardin colspan="2" colspan="2" colspan="4" X Steven Williams colspan="2" colspan="2" colspan="3" colspan="2" John Fitzgerald Byers Bruce Harwood colspan="2" colspan="5" Richard 'Ringo' Langly Dean Haglund colspan="2" colspan="5" colspan="2" Melvin Frohike Tom Braidwood colspan="8" William Mulder Peter Donat colspan="3" colspan="4" Margaret Scully Sheila Larken colspan="2" colspan="2" colspan="2" Well Manicured Man John Neville colspan="2" colspan="6" Teena Mulder Rebecca Toolan colspan="2" colspan="2" colspan="4" First Elder Don S. Williams colspan="2" colspan="2" colspan="5" Luis Cardinal/Hispanic Man Lenno Britos colspan="2" colspan="8" Pendrell Brendan Beiser colspan="2" colspan="2" colspan="7" Marita Covarrubias Laurie Holden colspan="3" colspan="3" colspan="2" Gray Haired Man Morris Panych colspan="2" colspan="7" Bill Scully Jr. Pat Skipper colspan="3" colspan="6" Third Elder John Moore colspan="2" colspan="2" colspan="6" Diana Fowley Mimi Rogers colspan="4" colspan="4" Morris Fletcher Michael McKean colspan="5" colspan="2" colspan="2" Gene Crane Kirk B. R. Woller colspan="7" colspan="3" Knowle Rohrer Adam Baldwin colspan="7" colspan="2" Billy Miles Zachary Ansley colspan="5" colspan="3" Brad Follmer Cary Elwes colspan="8" colspan="2" Jackson Van De Kamp/William Scully Miles Robbins colspan="7" Toothpick Man Alan Dale colspan="8" colspan="2" Erika Price Barbara Hershey colspan="10"

Character Portrayed by Seasons 1 2 3 4 5 6 7 8 9 10 11 Scott Blevins Charles Cioffi colspan="2" colspan="2" colspan="6" Theresa Hoese Sarah Koskoff colspan="5" colspan="2" colspan="3" Max Fenig Scott Bellis colspan="2" colspan="7" Richard Matheson Raymond J. Barry colspan="2" colspan="2" colspan="5" Melissa Scully Melinda McGraw colspan="2" colspan="6" Alien Bounty Hunter Brian Thompson colspan="7" colspan="3" Dr. Charles Burks Bill Dow colspan="3" colspan="3" Albert Hosteen Floyd 'Red Crow' Westerman colspan="2" colspan="2" colspan="2" colspan="4" Jeremiah Smith Roy Thinnes colspan="2" colspan="2" colspan="3" colspan="3" Michael Kritschgau John Finn colspan="3" colspan="2" colspan="4" Susanne Modeski Signy Coleman colspan="4" colspan="2" colspan="5" Cassandra Spender Veronica Cartwright colspan="4" colspan="2" colspan="5" Second Elder George Murdock colspan="4" colspan="2" colspan="5" Arthur Dales Fredric Lehne/Darren McGavin colspan="4" colspan="2" colspan="5" Gibson Andrew Praise Jeff Gulka colspan="4" colspan="2" colspan="2" colspan="2" Ted O'Malley Joel McHale colspan="9" colspan="2" Einstein Lauren Ambrose colspan="9" colspan="2" Miller Robbie Amell colspan="9" colspan="2"

Fox William Mulder is played by David Duchovny, a trained FBI profiler who believes in the existence of extraterrestrial visitors and a government conspiracy to hide or deny the truth regarding extraterrestrial life. Mulder and his partner Special Agent Dana Scully work in the FBI's X files office, which is concerned with cases with particularly mysterious or possibly supernatural circumstances that were marked as unsolvable and shelved by the FBI. Mulder considers the X files and the truth behind the supposed conspiracy so important that he has made their study the main purpose of his life. After seven years partnered with Scully, Mulder is abducted by aliens at the end of the seventh season. Upon returning, he officially hands the X files to Special Agent John Doggett, who was hired in his absence. Mulder returns to assist the FBI in 2008, and permanently rejoins the bureau in 2016. He and Scully have a son together, named William.

Dana Katherine Scully is played by Gillian Anderson, a medical doctor assigned to debunk the work of Special Agent Fox Mulder. Together they work out of a cramped basement office at the FBI headquarters in Washington, D. C., to investigate unsolved cases labeled "X files". In contrast to Fox Mulder's "believer" character, Scully was a "skeptic", basing her beliefs solely on what science can prove. However, as the series progresses she becomes more open to the possibility of paranormal happenings. After Mulder is abducted by aliens, the eighth season sees the assignment of a new partner to Scully: Special Agent John Doggett. Later in the same season, she leaves the X files office to teach at the FBI Academy. Scully departs from the FBI permanently in 2002. Sometime between then and 2008 she finds work as a surgeon. In 2008 she returns to consult with the FBI. She returns to the bureau permanently in 2016 alongside Mulder.

John Doggett is played by Robert Patrick, an FBI special agent who makes his first appearance in "Within," the eighth season premiere. Doggett served in the United States Marine Corps during the 1970s and the 1980s. Later he joined the New York City Police Department and was eventually promoted to the rank of detective. After his son's death, Doggett took a job in the FBI working in the Criminal Investigations Division. In 2000 Deputy Director Alvin Kersh assigned him to the X files office as Scully's partner after an unsuccessful task force attempt to find a missing Mulder in "Without". He grows to rely on Scully's friendship, even though he knows he can never replace Mulder. He is later partnered with Monica Reyes, and together they depart the X files in 2002, when the unit is shut down.

Monica Reyes is played by Annabeth Gish, an FBI special agent who was born and raised in Mexico City, where her parents still reside as of 2002. Because she was raised in Mexico, Reyes speaks fluent Spanish. She majored in folklore and mythology at Brown University, and has a master's degree in Religious Studies. In 1990, Reyes enrolled in the FBI at Quantico, Virginia. Her first assignment in the FBI was serving on a special task force investigating satanic rituals. She is a longtime friend of Doggett's and serves as his partner on the X files after Scully's departure. Shortly after the closure of the X files in 2002 she was contacted by the Cigarette Smoking Man who offered to secure her a place among the designated survivors of end times, in exchange for her assistance. Reyes departed the FBI shortly thereafter, electing to take Spender's offer but with the intent on halting the invasion from within the syndicate.

FBI assistant director Walter S. Skinner is played by Mitch Pileggi. He served in the United States Marine Corps during the Vietnam War. During this time he shot and killed a young boy carrying explosives, an episode which scarred him for life. Skinner is originally the direct supervisor of Mulder and Scully, and of the X files. He later serves the same position for Special Agents John Doggett and Monica Reyes. Although he is originally portrayed as a somewhat malevolent character, Skinner eventually becomes a close friend of his subordinates. Skinner is responsible for the reopening of the X files in 2016.

Brad D. Follmer is portrayed by Cary Elwes. Follmer was an assistant director at the FBI. He had a romantic history with Monica Reyes that he brought up while trying to keep her away from the X files. His true motives were more political in nature and part of his sycophancy to Alvin Kersh. He did not believe in the X files and deliberately showed disrespect to John Doggett by calling him "Mr. Doggett" instead of "Agent". In 2002, new evidence concerning the murder of Luke Doggett came to light. John Doggett sought Follmer's assistance because he had worked on organized crime in New York City before coming to Washington. Reyes, however, recalled seeing Follmer accept a bribe from a mobster. Although he had convincingly claimed he was only paying an informant, the truth was as Reyes suspected: Follmer was crooked. Once the truth of Luke's fate was revealed, Follmer shot and killed the mobster who had nevertheless threatened to blackmail him concerning his bribe acceptance. Follmer's future at the FBI was left unresolved, although he would have likely faced criminal charges for his actions.

Diana Fowley is an FBI agent played by Mimi Rogers and first appeared in the fifth season finale "The End". In keeping with the show's history of ambiguity, Fowley's motivations were never explained, although many viewers assumed her to be deeply associated with the Syndicate conspirators and working against Mulder in his pursuit of the truth within the X files. As Fowley is an old fling of Mulder's, additional tension was generated on the show and among viewers because of a perceived rekindling of her former close personal relationship with agent Mulder and the possibility of Fowley coming between him and his trusted partner, Special Agent Dana Scully.

Deputy Director Alvin D. Kersh is played by James Pickens, Jr. Kersh was a Navy A 6 Intruder weapons officer during the Vietnam War. He is known for using the same instincts that served him as an aviator in the military to guide his career in the FBI. His role in the series is primarily that of a foil to Mulder, Scully and Doggett, constantly trying to undermine and get in the way of their work in the belief of his own superiority. As an assistant director, he temporarily became supervisor to Agents Fox Mulder and Dana Scully when they were assigned away from the X Files unit. During this time, the Cigarette Smoking Man could be seen in his office, reminiscent of his silent presence in Walter Skinner's office in earlier seasons. Kersh assigned Mulder and Scully mostly to menial tasks, such as terrorist details and Federal background checks. When they did investigate an X File behind his back, Kersh would charge them for expenses they incurred on the case, forcing them to pay out of their own pocket. He also attempted to separate Mulder and Scully, believing that Mulder threw away a promising career as a criminal profiler, but that Scully's career could still be saved. When Mulder and Scully were reassigned to the X Files Section, Kersh continued to climb the ladder, culminating in an assignment as deputy director. It was not long after his promotion that Mulder was abducted by aliens. Kersh assigned John Doggett to run the manhunt for Mulder. When Mulder and Doggett pursued an unauthorized case, Kersh was prepared to fire them both, but Mulder accepted full responsibility and was dismissed from the FBI. Shortly thereafter, Mulder disappeared again, and Doggett brought in Monica Reyes to help him investigate Kersh's involvement in the conspiracy surrounding Mulder's disappearance. The investigation turned up nothing. Although Doggett seemed convinced that Kersh was involved in the conspiracy, Kersh insisted that he was actually protecting Mulder. During the ninth season, the Toothpick Man, a key conspirator, could be seen in the company of Kersh, much like Cigarette Smoking Man before. In the end, Kersh showed a heroic side when during the season finale, he helped Doggett and Skinner free Mulder from a military prison. Following this, Kersh had to permanently close the X Files to appease his irate superiors. The X Files are still officially closed when Mulder consults with the FBI 6 years later when FBI Agent Monica Bannon goes missing, however, Kersh is noticeably absent.

Jeffrey Frank Spender is portrayed by Chris Owens. Spender was a skeptic who was assigned to The X Files after Fox Mulder's forced leave. Spender is the son of the Cigarette Smoking Man (also known as C. G. B. Spender, or CSM) and his ex wife, multiple abductee Cassandra Spender. Heavily involved in the Syndicate at that time, CSM abandoned the family when Spender was 12 years old. Shortly after Samantha Mulder was abducted and then returned, Jeffrey and Samantha were raised together by his father in California. Spender met Agents Fox Mulder and Dana Scully in 1998. That same year CSM began sending him letters, however Spender would return them unopened. Three years later, it is revealed in "William" that Spender survived the gunshot, but that he was subjected to horribly disfiguring experiments at the hands of his father. Posing as Mulder, he infiltrates Scully's house and injects William with a magnetite substance to seemingly "cure" the baby of his telekinetic powers. The motivation or repercussions of his actions are never fully explained. He testifies for the defense during Mulder's murder trial in "The Truth" where he reveals that Teena Mulder had an affair with CSM, and that he and Fox Mulder are half brothers. A DNA test conducted on a disfigured Spender in the episode "William" initially leads agents Scully, Doggett, and Reyes to believe he is Fox Mulder, thus lending further credence to Spender's claim that both he and Mulder are the children of the Cigarette Smoking Man. All three of the Lone Gunmen die in the episode "Jump the Shark," sacrificing themselves to save thousands from a terrorist created plague. Skinner arranges for them to be interred at Arlington National Cemetery, as a tribute to their brave deeds.

Melvin Frohike is portrayed by Tom Braidwood. Frohike was born circa 1953 in Pontiac, Michigan. Prior to joining The Lone Gunmen, he was an acclaimed tango dancer in Miami (under the stage name "El Lobo"). On giving up the tango, he toured the country with hippies before founding Frohike Electronics Corp., specializing in cable intrusion hardware. In 1989 at a consumer electronics show in Baltimore, where his company had a trade stand, he met John Fitzgerald Byers and Richard Langly and they subsequently formed a group publishing The Lone Gunmen newsletter. In 1989 he met Melvin Frohike and John Fitzgerald Byers at a consumer electronics show in Baltimore, and they subsequently formed a group publishing The Lone Gunman newsletter. Langly wears thick black rimmed glasses, heavy metal and punk T shirts (favoring the Ramones in particular) and jeans. He has long blonde hair (which sometimes leads to him being mistaken for a girl) and bears a striking resemblance to Garth Algar from Wayne's World. He idolizes Joey Ramone in particular. The Syndicate later discovers that Covarrubias has betrayed them and is providing information to Mulder. As a result, Syndicate scientists infect her with the black oil virus, so as to test a vaccine they have been working to create. A cured Covarrubias later makes contact with Krycek at the behest of The Smoking Man, who wishes to resume the work of the now eradicated Syndicate. However, Covarrubias and Krycek betray the Smoking Man and leave him for dead. In the series finale "The Truth," Skinner seeks Covarrubias as a witness in Mulder's trial for murder. She is called upon to testify, and she speaks about her involvement with the Syndicate. However, when she is pressed for further information about the continuation of the conspiracy, she clams up, and at Mulder's request she is dismissed from the stand, for fear that if she divulges certain knowledge, she will be killed. Writer Frank Spotnitz has described Covarrubias as "young, attractive, vital [and] dangerous" compared to the other characters working for the Syndicate. Holden has compared the character to Mata Hari, adding that "you can't really read what she's saying or what her intentions are".

Deep Throat is the first of Mulder's informants, leaking information to him to aid his investigations. As a member of the then unseen Syndicate, he is in a position to know a great deal of information. Deep Throat feels that the truth being kept secret from the public by the Syndicate needs to be known. He believes Mulder to be the one person capable of exposing this knowledge. However, he believes that there are certain truths that the public are not yet ready to know. In "The Erlenmeyer Flask," the finale of the first season, Mulder is taken hostage following his investigation into an alien human hybridization program. Fearing for Mulder's life, Deep Throat helps Scully to gain access to a high containment facility, where she manages to secretly remove an alien fetus for use as collateral in saving Mulder. In the subsequent meeting between the operatives and Deep Throat, he is shot and killed. The character later appears in dreams and visions experienced by Mulder during his recuperation on a Navajo reservation, and again years later while being experimented on by the Smoking Man. Deep Throat was inspired by the historical Deep Throat, Also cited as an influence on the fictional Deep Throat was X, the character portrayed by Donald Sutherland in the 1991 Oliver Stone film JFK. The character was intended to bridge the gap between Mulder and Scully and the shadowy conspirators who were working against them; and was conceived as someone "who works in some level of government that we have no idea exists". Hardin's performance has been cited as "the spine of the series", and his portrayal of the character has been met with positive reviews from critics.

The First Elder is portrayed by Don S. Williams. He was a high ranking member of the Syndicate. His exact position in the Syndicate was unclear, especially in regard to the Well Manicured Man, though at times he seemed higher ranking than the Smoking Man. He contacted Scully in person while Mulder pursued evidence of an alien autopsy on a train. He also obtained photographs taken by X of a meeting between The Smoking Man and Teena Mulder as proof that one of the Smoking Man's henchmen was a traitor. The First Elder set up a trap to reveal the identity of the traitor and dispatched an assassin to kill him. X fell for the trap and was executed. He was killed along with the rest of the Syndicate by a group of Alien rebels in 1999. However, it later becomes evident that Krycek is actually an undercover agent working for the Cigarette Smoking Man. Krycek also assaults Assistant Director Walter Skinner and acquires a secret tape from him which reveals a US government coverup regarding alien visits to Earth. After a botched murder attempt on Scully results in the death of her sister, the Cigarette Smoking Man attempts to kill Krycek with a car bomb, but Krycek escapes. He lies low in Hong Kong for a short period, selling secrets acquired from the tape until he is found, beaten and apprehended by Mulder who takes him back to the US. Unbeknown to him, Krycek is under the control of an alien organism and he escapes Mulder before he is taken to a missile silo in North Dakota by the Cigarette Smoking Man. Having ejected the alien influence into an alien craft, he is left locked in a missile bay, screaming and banging on the door. When escaping a gulag in Russia, where Krycek pursues a mysterious rock, his left arm is amputated to prevent some experiments on him. Later in the series, Krycek can be seen switching sides as it suits him, occasionally helping Mulder, Cigarette Smoking Man and other people. He attempted to blackmail Skinner by infecting him with lethal nanotechnology, but ended up being thrown into a Tunisian prison when the Cigarette Smoking Man discovered that Krycek had stolen an alien artifact from him. In the last season 7 episode, "Requiem", Krycek apparently kills the Cigarette Smoking Man by pushing him down a flight of stairs. Doggett became suspicious of Rohrer when information was given to him from Rohrer that got a man killed, but it was not until Doggett saw Rohrer meet with Alex Krycek that he realized Rohrer was a member of the conspiracy. However, in the series finale, "The Truth", it is revealed that he survived, when Mulder breaks into Mount Weather. Rohrer chases down Mulder and in the ensuing scuffle Rohrer is electrocuted. Mulder is then taken into military custody and put on trial for Rohrer's supposed death. Eventually, Mulder breaks out with the help of Alvin Kersh, and with Dana Scully, headed to New Mexico for a final confrontation with the Cigarette Smoking Man, whom he discovered was still alive. Doggett and Monica Reyes went after Mulder and Scully to warn them that the conspirators knew where they were. Rohrer, alive and well, followed, intending to kill them all (including the Cigarette Smoking Man, who had long since outlived his usefulness to the conspiracy). However, as he approached Doggett and Reyes in the New Mexican desert, Rohrer died from exposure to magnetite. It turned out that the Cigarette Smoking Man figured out that magnetite killed the Super Soldiers, and consequently chose to hide in a pueblo saturated with it. He is involved in the Syndicate, a shadow organization within the United States government that exists to hide the fact that aliens are visiting Earth from the public. Spender is the leader of the Men in Black (MIB) in the series. To this end, he works with Alex Krycek to develop a vaccine, eventually testing it—successfully—on Marita Covarrubias. In the 1998 feature film The X Files, when Scully is infected with the black oil and taken to Antarctica, it is the Well Manicured Man who, having grown disillusioned with the Syndicate, gives Mulder the coordinates needed to find her and a sample of the vaccine needed to cure Scully. The colonists had kept secret a secondary characteristic of the black oil—that those infected with it for prolonged periods would gestate a new colonist lifeform, killing the host. Upon discovering this, the Syndicate vowed to work more closely with the colonists in the hope of being spared this fate, while only the Well Manicured Man wished to continue working on a vaccination for resistance. This rejection led to his betrayal of the Syndicate, and to him committing suicide by car bomb before his duplicity was discovered. The Well Manicured Man was portrayed by John Neville in all his appearances. Conceived as the "voice of reason" within the Syndicate, the character has been seen as representing an opposing viewpoint to that of The Smoking Man. The character has been positively received by critics. MTV's Tami Katzoff has called him a "legendary TV character", noting his "moral ambivalence about the work of his shadow organization" and his ability to show "empathy for Mulder and Scully". The San Francisco Chronicle Bob Graham has praised Neville's portrayal of the character in the feature film, calling his expository monologue "a Wagnerian demonstration of the art of declamation".

X, sometimes referred to as Mr. X, serves as an informant to Mulder, replacing Deep Throat in this capacity. While X's loyalties and his own agenda were often unclear, he has more than once proven that he at least does not want Mulder dead. In the episode "End Game", he is approached by Scully, who pleads that she needs to know where Mulder is, believing his life to be in danger. X reluctantly gives her the information after a fight with Skinner. In "731", X's loyalty to Mulder is further confirmed. Trapped on a train car equipped with a time bomb, Mulder is attacked by an assassin. X fatally shoots the assassin as he is about to step off the car, and boards with only enough time left to save either Mulder or the alien human hybrid the car was transporting, opting to save Mulder. In the season 4 opener "Herrenvolk", X's position as an informant is discovered by the Syndicate, and he is assassinated, but not before leading Mulder to his successor, Marita Covarrubias. After his death, X appears two more times—in The Lone Gunmen origin story "Unusual Suspects," set before his death, and as a ghost in the series finale, "The Truth". X is portrayed in the series by Steven Williams, and made his début in the second season episode "The Host", although the character would not appear on screen until "Sleepless", two episodes later. The role had originally been conceived as a female, with Natalija Nogulich cast in the role, however her initial scenes were deemed unsatisfactory by the producers, leading to her replacement. Williams' portrayal of X was intended to introduce a personality completely different from the character's predecessor, Deep Throat, and has been positively received by critics and fans.

Conrad Strughold is a fictional character played by Armin Mueller Stahl in the 1998 motion picture The X Files: Fight the Future. Strughold, a German scientist and entrepreneur, is the leader of the Syndicate. The Strughold mine in remote West Virginia, where the Syndicate secretly kept files on and tissue samples of abductees, is named after him. In the film, he authorizes Dana Scully's abduction, seeing it as a way to effectively break Fox Mulder's spirit, and as a more profitable alternative to outright killing Mulder. He lives in Tunisia. It is believed that he has Nazi ties and is unable to enter the United States because it would draw too much attention to the Syndicate. Strughold survived the demise of the Syndicate in season 6, though as of the end of the series, he is probably either dead, in hiding, or working with the New Syndicate (though the last option is unlikely). He is possibly the only member of the Syndicate to like or trust the Cigarette Smoking Man, as they are shown as having a slightly more cordial and far less adversarial relationship than with the other members. The season 6 episode "One Son" features a scene where Scully recounts the activities of Diana Fowley in the early 1990s, in which she monitored MUFON groups in Europe and took weekly trips to Tunisia, the implication being that she was reporting to Strughold during her time on this assignment. He is almost certainly named after Hubertus Strughold, a Nazi scientist who came to the US during Operation Paperclip after the end of World War II. (The original episode to show the mine in West Virginia was season 3's "Paper Clip", although Strughold himself did not appear in this episode, or in any television episodes of the show).

Section Chief Scott Blevins is portrayed by Charles Cioffi. Blevins was a top official in the Federal Bureau of Investigation who was bankrolled by Roush Pharmaceuticals, the same group that bankrolled Michael Kritschgau. Later that year, Section Chief Joseph McGrath went over Blevins's head in an attempt to order a shut down of the X files. Mulder and Scully would be later placed under the supervision of Assistant Director Walter Skinner,

In 1997, Blevins led a joint FBI committee that was investigating the legitimacy of Mulder's work on the X files and his apparent suicide. as a digital photo expert and using the nickname Chuck, Dr. Burks was occasionally returned to as an open minded expert more in line with Mulder's belief in the paranormal than Scully's skepticism. His contributions to X Files investigations include aura photography and sonic analysis, however he also delved into languages and mysticism (in the episode "Badlaa", in which he is introduced to John Doggett as an old friend of Fox Mulder's).

Luis Cardinal is portrayed by Lenno Britos who appeared in a total of four episodes. Cardinal was a Nicaraguan mercenary working for the Cigarette Smoking Man, briefly partnered with Alex Krycek, at which time he killed Dana Scully's sister, Melissa Scully, in a case of mistaken identity. Dales spent the rest of his career investigating X Files before an early retirement. He lived in Washington, D. C. before moving in 1999 to Florida, Theresa nearly died but was saved by Jeremiah Smith. She later appeared in a slide show in "Three Words". The name for this character came from Gillian Anderson's real life friend from growing up in Grand Rapids, Michigan.

Senator Richard Matheson, portrayed by Raymond J. Barry, was a politician that took a liking to Fox Mulder and was interested in his work at the FBI. After the X Files were shut down in 1994, Matheson prompted Mulder to visit the Arecibo observatory in Puerto Rico to continue his search for the truth. Eventually, Matheson distanced himself from Mulder because he felt his political career might be in jeopardy. Later that year, Mulder went to Matheson's office in an attempt to contact him to gain information about Scully's abduction, but he was intercepted by X, who told him that Matheson could not give him the information he wanted without risking himself. He later gave Mulder a lead that led him to government program to import Japanese scientists to the US after World War II. Mulder ran into Matheson years later while investigating a mysterious illness contracted by Walter Skinner. Matheson was directly involved in an illicit deal concerning nanotechnology. The incident further soured relations between Mulder and Matheson. In 1973, the group of men became organized as the Syndicate. As part of the colonization plot, the members of the Syndicate were to exchange a loved one each for an alien fetus. Possession of the fetus would allow the Syndicate to begin development of an alien human hybrid. Mulder was against this exchange and did not appear at El Rico Air Force Base with a loved one as planned. In order to secure the exchange, an alien spacecraft was sent to retrieve his daughter, Samantha, who had been selected by Mulder instead of his son, Fox. Horrified at his own involvement, Mulder came up with the plan to create a vaccine against the alien virus that would be used during colonization. Even though he got his way and development of the vaccine began, The Cigarette Smoking Man later convinced a bounty hunter to heal her.

Special Agent Pendrell is portrayed by actor Brendan Beiser. Agent Pendrell first appeared as an employee of the FBI's Sci Crime Lab who assisted Agent Scully in her investigations in the third season. Pendrell shows a helpful demeanor, a self deprecating nature and nurses an obvious crush on Agent Dana Scully. He provides analytical assistance to Mulder and Scully over the course of several episodes, showing a particular aptitude for working with computers and biological materials.

Gibson Andrew Praise is a character portrayed by Jeff Gulka. Gibson is introduced as a young chess prodigy who thwarted the assassination attempt on his life by stepping back out of the path of a sniper bullet. Jeffrey Spender was assigned to investigate the case, but Fox Mulder intruded on the briefing and immediately came to the conclusion that Gibson sensed the shot pre cognitively. The investigation led Dana Scully to find that Gibson had an unusual level of development in one brain lobe not yet fully understood by neuroscience. Mulder thought Gibson might be the key to understanding human potential and to everything in the X Files. He interrogated the would be assassin in prison, who said the boy was a "missing link", and Mulder jumped to the conclusion that Gibson had alien genetic structure and was proof of ancient astronauts. His final appearance was in the series finale, where it was revealed that Mulder had been hiding with Gibson in New Mexico for the duration of his ninth season absence. Gibson volunteered to be a witness at Mulder's trial, despite Mulder's objection that he should stay hidden. After Mulder and Scully leave to make their final escape, Agents Doggett and Monica Reyes vowed that they would try to keep him safe – a promise that Gibson took with a grain of salt, knowing the capabilities of his past captors. They all attended Emily's funeral and were distraught for Scully.

Margaret "Maggie" Scully was portrayed by actor Sheila Larken. Margaret, or "Maggie" as she was called by her husband, Bill Scully, is the mother of Dana Scully and her three siblings: William "Bill" Scully, Jr., Melissa Scully and Charles Scully. She may have a bit of psychic intuition – when Dana is kidnapped, Margaret confessed to Mulder that she had had a premonition about Dana, but was afraid to tell her skeptical daughter. In 2016, Margaret suffered a heart attack and went into a coma. Dana revealed that Margaret's advance healthcare directive allowed life support to be applied, however she was unaware that Margaret had revoked it and replaced it with a DNR a year earlier. After hearing Charles Scully's voice on the phone, Margaret briefly awoke from her coma before passing away, with Mulder and Dana by her side. Her last words to Mulder were "My son is named William, too".

Melissa "Missy" Scully was portrayed by Melinda McGraw as an adult and Rebecca Codling and Lauren Diewold during childhood flashbacks. Melissa was the sister of Dana, Bill and Charles, and the daughter of William and Margaret. Melissa believed in new age mysticism, whereas Dana was a firm believer in hard science. Melissa came to see Dana when she had returned to the hospital after her abduction and claimed she could feel Dana's spirit was still inside her body. The Second Elder's final appearance was in "Two Fathers". The Cigarette Smoking Man called the Second Elder at his home to inform of the Rebel attack. He had called an emergency meeting of the Syndicate and encouraged the Second Elder to attend. The Second Elder indicated that he would catch the next plane, then hung up the phone. Shortly afterward, he was killed by a Rebel, which then infiltrates the Syndicate's meeting disguised as the Second Elder. The rebel in disguise is later killed by Alex Krycek after a failed attempt by Jeffrey Spender. His role in the series was the leader of the New Syndicate. During the ninth season he worked within the FBI.

Jackson Van De Kamp (born William Scully III) is the son of FBI Special Agent Dana Scully and Fox Mulder as well the adopted son of Mr. and Mrs. Van De Kamp. He was born in the eighth season finale, "Existence". Throughout the last two seasons of the series William was encompassed by an aura of mystique, ranging from his origin to the apparent supernatural abilities he possessed. At some point, Scully made the decision to have a child through in vitro fertilization, and asked Mulder to be the sperm donor, to which he agreed, as revealed via flashback. In "Essence", Mulder's inner monologue reflects: "How did this child come to be? What set its heart beating? Is it the product of a union or the work of a divine hand?" suggesting William may have been conceived naturally through intercourse, by some paranormal intervention, or perhaps some measure of both. In The X Files: I Want to Believe, and the tenth season, both Mulder and Scully referred to William as their son. However, in season 11 it is revealed that William is in fact the son of C. G. B Spender, The Smoking Man. He was medically conceived in season 7 while Scully was unconscious. He is played by Miles Robbins while Jerry Shiban (the son of John Shiban) and several other children play him as an infant, Bentley Hixsons plays him as a young child, Chase Nicholson plays him as a preteen, Austin Dunn plays him as a young teen, Keith Arbuthnot plays him as Ghouli, François Chau plays him as Peter Wong and David Duchovny plays him as Mulder. The version seen in Scully's dream is played by siblings Hannah Longworth, Aiden Longworth and Rowan Longworth as a child, preteen and teen respectively.

Eugene Victor Tooms is portrayed by Doug Hutchison. Tooms is an immortal genetic mutant who subsists entirely off of human livers and able to elongate and contort his body to inhuman degrees, hibernating for 30 years between his feeding periods. Tooms frequently steals personal items from his victims, keeping them as trophies. Tooms is later released and resumes his job as a dog catcher while staying at a halfway house. Tooms's efforts to feed on another victim are hampered by Mulder's vigilance. After framing Mulder for assaulting him and filing a restraining order against him, Tooms murders and feeds on his psychologist. Mulder and Scully track Tooms down to beneath a mall built over his apartment complex and previous lair. After a confrontation with Mulder in his newfound home, Tooms is trapped beneath an escalator and crushed to death when it is activated.