Linda Baldwin Linda, played by Lori Triolo, is the ex-wife of Tom and mother of Kyle. She appears throughout the first season. She and Tom have drifted apart during Kyle's time in a coma and Linda files for divorce. She is also friends with Dennis Ryland who notes he danced with her at their wedding. She is one of the first to realise Shawn was responsible for Kyle recovering from his coma. Tom moves back in with her and Kyle in an attempt to jog his memories. She helps Tom and Diana with retrieving Kyle from federal custody. By the second season, hers and Tom's divorce has been finalised. Her only subsequent appearance is in "Hidden", where she hides Kyle after he begins to realise he is Jordan Collier's assassin.
Kevin Burkhoff Played by
Jeffrey Combs, Kevin first appeared in the season two premiere episode "Wake Up Call", in which he was a patient in a psychiatric hospital. Kevin suffered from
paranoid personality disorder and had not spoken in six years, and was friends with a schizophrenic 4400 named
Tess Doerner. Tess used her 4400 ability to get everyone in the hospital to build a machine she saw in her mind, mistakenly believing that it would contact the future. When the machine was built, it created a pulse that released everyone from Tess' mind control and cured Kevin of his mental illness. It was then revealed that Kevin was a world-renowned neuroscientist and likely the "father of the 4400 technology". Kevin was the one who discovered how to cure the side effects of the promicin inhibitor during the season two finale. In the third season, Kevin begins to inject himself with promicin in order to gain some type of 4400 ability. The shots he took disfigured his appearance by causing wounds on his chest and loss of his nails, though in exchange it granted him rapid (but inconsistent) healing of muscle tissue. This was first demonstrated when he put a scalpel through his hand and it healed within seconds. After several months of injections, his entire body was covered in lesions and decaying tissue, but his regenerative abilities were now fully active, as he literally resurrects himself after taking four nine millimeter rounds to the chest at the hands of one of
Dennis Ryland's agents and being placed in a body bag for autopsy. After a failed attempt by him and Tess to perform the same promicin-injection procedure on
Diana Skouris, he shed his skin like a snake, revealing an untarnished appearance. Kevin now possesses the paranormal ability to regenerate. Kevin and Tess Doerner ran away together in the season three episode "
The Ballad of Kevin and Tess"; later, in the episode "
Terrible Swift Sword", it is revealed that they went to work at a small town garage where
Tess used her ability to bring customers to the local businesses. Kevin and Tess were recruited to help
Jordan Collier steal
Dennis Ryland's promicin, and they are currently in hiding with Collier. During their time with Collier, without proper medication, Tess once again comes under the influence of her schizophrenia and leaves, causing Kevin to follow her. He is later seen in a small town where Tess forces most of the denizens to participate in her "sweet sixteen", but due to an intervention by
Shawn Farrell, Tess is cured of her illness. Kevin is then enlisted by Shawn to create a promicin-profiency test that can tell if one is going to survive a promicin shot or not. Before he is finished, Kevin is then kidnapped by
Kyle Baldwin, who believes the test will ruin the promicin distribution movement. The serum Kevin Burkhoff injected himself with to gain an ability was not the same solution of pure
promicin that was used to cure the 4400 of the inhibitor. Kevin makes it very clear in "
The New World" that he is injecting himself "with a modified version of the promicin serum". The promicin given away to the public by
Jordan Collier comes directly from
Isabelle's veins, which is why the promicin shots have a 50-50 chance of either killing the recipient (with multiple brain aneurysms) or giving an ability.
Susan Farrell Susan (Chilton Crane) is the sister of Tom Baldwin and the mother of Shawn and Danny. She is a single mother, her husband having left her years previous. She is first seen reacting to Shawn's return and welcomes him home but reacts badly when his powers manifest and cause him to begin draining Danny's life force. Despite this, she attempts to maintain a relationship with Shawn after he moves to the 4400 Centre, inviting him over for a family meal to try and build bridges between him and Danny, and enthusiastically supporting his attempt to marry Isabelle. During the fourth and final season, Shawn moves back in with Susan and Danny for a short while following his estrangement from Collier. She later discovers that Danny has taken a promicin shot after getting confirmation from Kevin that it is safe for him. However, she is the first person to succumb to Danny's contagious promicin. She dies in the series finale as a result of promicin rejection, with her and Danny later being buried alongside each other.
Marco Pacella Marco Pacella (
Richard Kahan) is in charge of NTAC's theory room, and is the one who initially proposed that each 4400 has caused a "ripple effect". He often appears to somewhat resent his colleagues, at one point labeling them as the "Two most annoying people on the planet". His relationship with the NTAC agents
Tom Baldwin and
Diana Skouris is strained at first; Tom had little patience for the Theory Room's methodology, and Diana claims that he intimidates Marco and his colleagues. When Tom prepares to rescue his son
Kyle, Diana goes to Marco for help. At this point, Marco hints at his feelings toward Diana, claiming that he isn't helping for Tom's benefit; the look of shock on Diana's face implies that she had been completely unaware of his feelings. Marco continues to aid the NTAC agents from the Theory Room. His friendship with Diana grows, with her teasing him affectionately. He makes a forgery of Diana's daughter
Maia Skouris' vision diary, so that Diana will not have to hand the real one to the government for analysis. Maia had even predicted Marco's future death in her diary. Although surprised when he read about it, he thought that the manner of his foretold death was "actually pretty cool". Marco and Diana finally begin a relationship during the season 2 finale, "
Mommy's Bosses", as Marco says he will support Diana through the long process of bringing the
promicin inhibitor conspirators to trial. In the season 3 episode "
Blink", Diana ends the relationship with Marco as she believes she is using him to avoid becoming close to a man more her type. Despite being hurt at the rejection, Marco is never shown to be anything other than supportive of her. Whilst dating Diana, Marco had become friendly with her daughter Maia, and Maia asks after him even after the breakup. Marco informs Diana that April is missing and in possession of promicin, leading to Diana's reinstatement into NTAC and move back. He later believes that making conspiracy movies is the ability of 4400 Curtis Peck. When Diana is searching for a safe place to hide Peck, Marco uses his apartment (leading to a momentary awkwardness as he and Diana remember their brief relationship) as a base for Peck to write his newest script, although Peck is later compromised by "The Marked". It is Marco who deduces the location of
Jordan Collier's base in Seattle, before Collier reveals his "
Promise City" to the US government. When Marco's colleague uses his own promicin-induced ability, putting many of the principal "players" into a game of survival, the failed relationship between Marco and Diana is re-examined. Maia does not understand why Marco no longer visits them, and Marco admits to Diana that he does find it a little hard seeing her every day. Diana asks if he would be willing to give genuine friendship a try, and offers him an invitation to dinner with her and Maia. After being infected by a promicin-inducing virus in "The Great Leap Forward", Marco can seemingly
teleport to any place he is thinking of, as he appears in Promise City after looking at a photograph of the location.
Tess Doerner Tess Doerner (
Summer Glau) disappeared April 3, 1955. Tess is first seen in the second-season premiere episode "
Wake Up Call". She is a
paranoid schizophrenic living in a
psychiatric hospital. She has mentally taken control of the patients and staff at the hospital to undertake a task of building an unknown structure. Once completed, an attempt at powering up this unknown device seems to fail, until Tess's friend and protector
Kevin Burkhoff speaks for the first time in six years; he has been "woken up" by the device and is revealed to be the probable "father" of 4400 technology. Tess is later seen in the episode "
The Ballad of Kevin and Tess", when
Tom Baldwin and
Diana Skouris are looking for Kevin. Tess claims not to have seen him; however, secretly she is keeping Kevin at her house, as he has mutated due to his
promicin experiments. Tess has also been instructing Diana to come to her house using her abilities so that Kevin could inject her with promicin. After the events that follow, Kevin and Tess run off. In the episode "
Terrible Swift Sword",
Jordan Collier receives help from 4400s with the ability to trace people to track Kevin and Tess and discovers where they are hiding; he then goes to visit them and enlists them in his plan to steal
Dennis Ryland's stores of promicin. She uses her ability to prevent
Richard Tyler from destroying the entire supply of stolen promicin in the third-season finale "
Fifty–Fifty". In the fourth season premiere, Tess suffers a relapse into schizophrenia and begins "seeing" dead people. In the episode "
Daddy's Little Girl", Tess's schizophrenia is finally cured by
Shawn Farrell.
April Skouris April (
Natasha Gregson Wagner) is the artistic free-spirited sister of NTAC Agent
Diana Skouris. When she was introduced she was the "black sheep of the family": unlucky, unmarried, steady job-less, and very untrustworthy.
Maia, was briefly tricked into using her ability to choose lottery tickets and wager on sports for her "Aunt April". After this was discovered, Diana told April she was not allowed to see Maia and to come back one day when she is a better person. Later in the series April returns with a handsome boyfriend named Ben and a successful job at her own tattoo shop. Although things seem up for her, things take a wrong turn. She proves to be unlucky in her relationship with Ben (
Brennan Elliott), recently losing him to her sister, Diana. April becomes depressed and coming to the realization that her life is pointless she takes a promicin shot, gaining the ability to make anyone truthfully answer any direct question she asks. She used this ability to make a living blackmailing people, and falls in love with a man named Colin. However, one of her "marks" is the vice president of a
Fortune 500 company which paid for hitmen and was selling defective armor to the military. The "mark" has April's new boyfriend murdered. Shocked, sad, and frightened at her loss and the new danger she is in, April returns to Diana for help and for a short time helps them uncover the killer using her ability. April uses her powers to expose the head of the corporation to NTAC, and is later employed by the federal government, using her powers in interrogations. She and Diana leave off on a more positive note than before.
Gary Navarro Prior to his abduction (January 5, 1973), Gary Navarro (
Sharif Atkins) only worried about baseball and getting to the Major Leagues. After his return, Gary hoped to continue his life's goal. Although NTAC Agent
Tom Baldwin had promised to help him gain control his recently emerged telepathic abilities, Gary was swept up and made a spy for NTAC, an
NSA agent, and eventually a member of the 4400 radical terrorist organization, Nova Group. Gary was first used by NTAC to spy on the newly opened
4400 Center, reading the minds of Jordan Collier to dig up information. After he was uncovered as a spy, he was taken by the NSA to be used to find 4400s from hostile nations. His job was to eliminate them before they could be used as weapons. Finding out he'd been used to kill his own kind pushed Gary to then join Nova. While working for Nova, Gary was captured when he attempted to murder
Dennis Ryland. Agents loyal to Ryland subjected Gary to torture, including
waterboarding, at the NTAC facility. When Tom Baldwin objected to his cruel punishment, NSA arranged to remove Navarro to another remote facility. Navarro was gladly freed in transit by the Nova group but after T.J. Kim's murder, Gary became dissatisfied with the Nova Group's operations and tired of the war, so he quit. After a larger controversy where he escaped re-capture by NTAC thanks to
Alana Mareva, Tom finally fulfilled his promise to Gary and helped him flee from the United States. Gary is currently a fugitive, reportedly in Canada.
Nikki Hudson Nikki (
Brooke Nevin) is the Farrells' neighbor and was Danny's girlfriend, until Shawn returned. Nikki and Shawn developed feelings for each other and dated until Shawn ran away to the 4400 Center. She returns later asking for Shawn's help curing her
cancer-stricken father. They seem on the verge of renewing their relationship but Shawn calls it off, fearing that
Isabelle will try to kill Nikki as an obstacle to her and Shawn's happiness.
Danny Farrell Danny (
Kaj-Erik Eriksen) is
Shawn's younger brother who, because Shawn "stole" his girlfriend, is a staunch anti-4400 college student. Danny goes to the same college as Kyle. During season two, however, Matthew Ross suggested to Shawn that he should mend things with his family to help his image. Since then, Danny has healed his relationship with his older brother, though tensions still exist between the two. The antagonistic relationship between the brothers flares up again in season four. Danny has felt that becoming a lawyer, in view of the powers possessed by promicin-positive individuals, has become pointless. In spite of his brother's advice, Danny wants to take promicin, and he mocks Shawn's warnings as fear that Shawn will no longer be the "special one". After realizing that taking promicin is Danny's own choice, Shawn gives a shot to him, but asks Danny to wait a few weeks to think it over. In
Tiny Machines, Danny, having heard about the test being developed by Kevin Burkhoff to determine whether or not an individual can tolerate promicin, approaches his brother at the 4400 Center. Though the test had not yet been completed, Burkhoff was able to predict, due to Danny's prominent
Corpus callosum, that he would indeed survive if he took the shot. After doing so, Danny was unharmed - however during a visit home, in which he reveals that he is now "P-Positive" to his mother over drinks, the latter begins to exhibit signs of an aneurysm similar to those induced when individuals who can't tolerate promicin take the shot. After many deaths, Danny realizes that his body is creating more promicin than it can contain and is involuntarily releasing it, infecting many. Much like the shots, the victims have a 50% chance of either surviving or acquiring a special ability. He eventually seeks Shawn's help and is put on the promicin inhibitor, but is left with an ultimatum: die from the buildup of promicin or get off the inhibitor and risk infecting others. Not wanting to kill anyone else, Danny forces Shawn to euthanize him. Meanwhile, the ensuing chaos of people being infected by promicin is used by
Jordan Collier to bolster the support of his movement and take control of Seattle. Danny Farrell and Jordan Collier have the exact opposite ability.
Matthew Ross Matthew (
Garret Dillahunt) was a lobbyist in the Collier organization who advises Shawn after
Jordan Collier's death. Matthew ran the day-to-day business of the 4400 Center and it is hinted Collier gave him specific instructions of what to do. Early episodes in the third season suggested that Matthew knew more about the 4400 and
Jordan Collier's assassination than he had revealed. When
Isabelle Tyler was contemplating suicide, Ross told her she was nearly invulnerable, but offered her a syringe that he claimed would kill her. In a later episode, a similar toxin was given to
Tom Baldwin from the future in order to neutralize
Isabelle. Matthew is later murdered by
Isabelle when she inflicted an instantaneous
stroke upon him. He had manipulated her for some time, and informed her that her purpose was to destroy the 4400. He implied that his loyalty lay with a faction from the future, one that opposed the 4400 project. This faction would be described to Tom Baldwin by the future people, and were described as cold and brutal in their methods. In the fourth-season episode
"The Marked", it is revealed through Curtis Peck's ability that Ross was among a ten-strong group of prominent individuals in society who have had their consciousness "hijacked" by the 4400-opposed faction. A side-effect of this operation leaves a
mole underneath the subject's left earlobe, along with a vaguely X-shaped mark (hence the title of Curtis'
Independent film and thus the episode). This mole is never actually visible in any scenes where Matthew was present, but it is explicitly revealed that he was the first known "Marked".
Heather Tobey A school teacher, Heather (Kathryn Gordon) disappeared March 2, 1974. Her ability is to allow people to realize their full potential with regard to any special talent they may have. She unlocked artistic potential in several of her students. After several parents complained about their children being "altered", she quit. In the third season, she works at the 4400 Center's school. While taking the
promicin inhibitor, her ability only worked on children, but without the inhibitor she can help adult 4400s focus their abilities, e.g., she helped
Richard Tyler gain greater control over his telekinetic abilities. She now works as an assistant to Shawn Farrell at the 4400 Center.
Cassie Dunleavy Cassie Dunleavy (Tristin Leffler) is seemingly the physical manifestation of
Kyle Baldwin's ability. She makes her first appearance in the fourth-season premiere, "
The Wrath of Graham". Cassie first approaches Kyle in a park where she poses as an art student. During the course of their conversation she suggests Kyle inject his cousin,
Shawn Farrell, with
promicin to snap him out of his coma. Kyle takes her advice and Shawn is awakened. Kyle later returns to the park to tell Cassie what happened, but she is not there. He tries to track her down at the art school she mentioned, but no one has ever heard of her. When he next sees Cassie (in "
Fear Itself"), he confronts her with this information. She does not tell him who she really is but instead encourages him to enter a house whose owner maintains a makeshift museum devoted to the 1918 cult, the White Lights. Among the artifacts Kyle encounters there is a book that describes the coming of a messiah whose portrait physically resembles
Jordan Collier. There is also mention of a healer and a shaman, whom Cassie later reveals as Shawn and Kyle, respectively. She also reveals in this episode that she is Kyle's ability, and only he can see her. In "
Audrey Parker's Come and Gone", Cassie instructs Kyle to steal the book describing the White Lights prophecies that he had read in the previous episode. Kyle does as she asks, leaving a $100 donation for the curator as compensation. Cassie later appears while Kyle is reading the book to tell him to meet her at the intersection of Forbes and Shady at 2 a.m., "where it's all beginning". She warns him that if he doesn't show, he'll never see her again. Kyle does show up at the appointed time, and is there to witness a car crash that leads to the liberation of
Isabelle Tyler, in transit to her new holding facility. Later, in the episode entitled "
Tiny Machines", Kyle finally begins to lose faith in the wisdom of Cassie's advice. When Isabelle, under the influence of the now-Marked Tom Baldwin, turns her back on the movement and kidnaps Jordan Collier, Kyle angrily accuses Cassie of deceiving and manipulating him. Her response indicates that Isabelle's betrayal was all part of a larger plan, and that in Jordan's absence it will fall on Kyle to assume leadership of Promise City. In the follow-up book, Promises Broken by David Mack, Kyle finally realizes that Cassie is not always looking out for his interests and was leading him in dark directions by sometimes speaking through him and even using him as her puppet. She is described as being "more than a little crazy, and she's got a mean streak".
The Marked The Marked are a group of people belonging to the anti-4400 faction in the future, and they are first revealed in their
eponymous episode. They consist of ten "elites" sent from the future, whose goal is to preserve the timeline as it originally proceeded and to stop the 4400 - in particular,
Jordan Collier. The Marked have taken over the minds and bodies of prominent people in the present day, manipulating the world in total secrecy. Due to the procedure involved in the implantation, the Marked cannot develop powers by taking promicin. They are revealed to have an X-shaped mark behind the left earlobe, as described in 4400 Curtis Peck's trailer for his film
The Marked, which would have unveiled the entire conspiracy. The only explicitly revealed agents thus far are Drew Imroth, the CEO of the Ubient Software Corporation; Rebecca Parish, the director of National Intelligence; and
Matthew Ross. It was Ross who primed The Marked's ultimate weapon
Isabelle Tyler to destroy the 4400, although the plan faltered when she murdered him. When Tom Baldwin is sectioned in a mental hospital for reporting Curtis Peck's claims of conspiracy, The Marked implant a
sleeper agent inside him. Drew Imroth later reassures his comrades that when they need him, Baldwin will be there for them. After seeing numerous memories belonging to another person, Tom Baldwin is eventually overcome by the being formerly possessing Matthew Ross. Baldwin then uses his NTAC status to his advantage, capturing Isabelle Tyler and blackmailing her into taking back her abilities. Following an attack on Ubient Software Corporation by a promicin-positive, the rest of The Marked have Drew Imroth kill his host so that he can be implanted into another host, Jordan Collier. Baldwin then forces Isabelle to kidnap Collier. When Tom Baldwin is later freed from The Marked's control, he tries to rescue Collier, but is captured. However, Isabelle soon turns against The Marked, killing Rebecca Parish and freeing Baldwin and Collier at the cost of her own life. Baldwin, still retaining his memories of being one of The Marked, then gives Collier a list of the remaining seven. Known members of
The Marked include: • Matthew Ross (deceased, agent transferred) • NTAC agent Tom Baldwin (alive, agent deceased) • Ubient CEO Drew Imroth (deceased, agent transferred) • Jordan Collier (agent status unknown) • National Intelligence agent Rebecca Parish (deceased, agent status unknown) ==Minor characters==