Carolyn Martens is one of the characters in the BBC series Killing Eve. She is the Head of Russia Desk at MI6.
Charismatic, erudite, incredibly well-read and irreverent, Carolyn is a principled yet ruthless leader in her field. As a young agent on the ground in Moscow in the 80s, she cultivated one of MI6’s most valuable assets and has since saved the world at least three times.
Naturally suspicious, a spate of un-attributable assassinations around the world has prompted her to set up a secret unit to investigate.
A literal and strategic woman, Carolyn is smart enough to know when someone has a specific talent, and is not shy about pointing out qualities or perspectives other people have that she might lack. She sees that Eve thinks outside the box and where everyone else has dismissed her, she admires and encourages her. She herself is not a maverick, but she’s very good at hiring them.
Having set up the secret unit, Carolyn puts Eve in charge of it. She needs a group that can be invisible and work without the restraints of a typical MI6 unit.
Carolyn has formed intimate relationships with her foreign counterparts on more than one occasion –an occupational hazard. She is on her fourth husband and her only child went to boarding school; she’s obsessed with her work. 
Significance in series Edit
Even though it is Saturday, Eve has to go into work at MI5. She enters the meeting late and sits down next to her boss, Bill Pargrave. Frank Haleton introduces everyone to Carolyn Martens who runs the MI6 Russia Desk. Carolyn informs them of the assassination of Victor Kedrin, a high-profile Russian politician. He was leaving a sushi restaurant near Stephansplatz with his girlfriend, Kasia Molkovska, when his femoral artery was sliced open. The girlfriend fled the scene and was picked up in Hammersmith. Eve and Bill are to provide diplomatic protection for Kasia. Eve tells Carolyn that it was a woman who assassinated Kedrin.
After Kasia is murdered, Bill sits with Eve and tells her she did the right thing. Frank and Carolyn enter and Frank blames Eve for conducting an illegal investigation, manipulating a witness, putting a minor in danger, and failing to protect Kasia. Eve confronts Frank about the assassin being a woman and Frank fires her. Eve and Bill both call Frank a "dick-swab" and Frank fires them both.
Eve is at home watching television with Niko when her doorbell rings. Carolyn invites her to walk to the corner shop where she reveals to Eve that Villanelle has been operating for two years across ten countries. She offers to buy Eve breakfast on Thursday at 9 am at the Purple Penguin by Charing Cross.
Eve shows up at the Purple Penguin to meet with Carolyn. They discuss Eve's background: how she was born in the UK but moved to Connecticut when her parents split up and came back when her father died. Carolyn confronts Eve with a folder of documents on female assassins they found when they were going through Eve's computer after she was fired. Eve explains that she believes there is a female assassin running around who doesn't have a specific signature but has a definite style.
Carolyn takes Eve to a decrepit building where a dingy office has been set up with all of Eve's information on the female assassin. Carolyn has set up an "unofficial-official" investigation that she wants Eve to run secretly. Kenny enters and is introduced to Eve as the person who has been gathering the evidence. Eve is allowed two more people for her team.
Carolyn is in the office with Elena and Kenny waiting for Eve and Bill to arrive to let them know that there has been another assassination. Eve thinks that Carolyn is referring to Carla de Mann but Kenny tells her that it was a Chinese colonel, Zhang Wu, who has been killed. The name the assassin gave to the receptionist was "Eve Polastri". Outside, Eve paces as she begs Carolyn to keep her on the team. Carolyn asks her what she wants to do.
Eve meets Carolyn at a butcher shop. She tells Carolyn about a work party a year ago where Frank got really drunk and emotional about not being able to afford to send his kids to St. Henry's school. Kenny is tracking Frank down so they can bring him in for information.
As Elena drives Eve to Bletcham, Elena tells stories about how Carolyn has saved the world several times going all the way back to the '80s when she stopped an ex-KGB agent from selling plutonium.
Eve and Elena take Frank to a safe house where Max Sanford will be looking after him. Carolyn is at the safe house and Frank starts making excuses before complaining that he is having a panic attack. Carolyn gives him five minutes to change clothes under Max's supervision. Elena brings tea to Eve and Carolyn before heading back to the office. Max tells Carolyn Frank won't come out so Carolyn goes to Frank's room and cradles him in her arms, getting him to talk. Frank reveals that "The Twelve" know everything about Frank, including his deceased wife's cancer treatments. They were willing to pay for her treatments in exchange for Frank telling them the big picture of what is going on at MI5. Frank assumed they were Russian SVR agents and was the one who told them that Eve was still investigating. Frank explains there is a pattern to Villanelle's kills and the plan is to destabilize and cause chaos.
Carolyn tells Eve that the police have found Diego's body but no one else. Carolyn asks after Kenny since Bill's death because Kenny's own father died a few years ago. Eve promises to keep an eye on him.
After Villanelle leaves Eve's house, Eve rushes over to Carolyn's house, interrupting her at dinner with friends and her son, Kenny. Carolyn takes her and Kenny into another room and Eve explains that Villanelle has her phone, which gives her access to Frank's interview and his location. She also asks for protection for Niko.
Outside the safe house, police in tactical gear move in. Carolyn and Eve listen from a van as they report back they have a male in need of medical assistance. Eve rushes in to find Max still alive but Frank is dead in the bedroom. He is laid out on the bed, wearing Eve's dress, his knob chopped off.
In Eve's office, Kenny reports that Nadia was picked up in Bletcham by Russian intelligence and was taken to the same prison Villanelle "died" in three years previously. Eve asks Carolyn if they can go to Moscow to question Nadia. Both Kenny and Elena opt out of the trip.
In Moscow, Eve and Carolyn take a taxi as they discuss what the Twelve might want and review Nadia's and Oksana's prison files. Carolyn puts on makeup, prompting Eve to ask about Carolyn's Russian contact, Vladimir Betkin, and how well she knows him. They arrive at the hotel and check into their rooms.
At the bar, Carolyn and Eve are having drinks before Vladimir arrives. Carolyn gives Eve advice on her personal life, telling her she shouldn't have one because it is a detriment to the people in her life. Vlad shows up and greets Carolyn before introducing himself to Eve. He has another person joining them: Konstantin. Carolyn greets him with familiarity and they soon fall into retelling old stories. Carolyn eventually gets to the matter of Nadia but Vlad is withholding. She brings up the Russian sleeper agent who was assisting Frank and asks if either of them are investigating Victor Kedrin's murder. Carolyn offers an exchange: for a meeting with Nadia, she will provide them with the information they received from Frank before he was murdered. Eve reveals that Villanelle/Oksana broke into her house to have dinner and thinks Nadia can provide information about her. Vlad capitulates to one interview as long as Konstantin goes with them to the prison. As Eve and Carolyn head to their rooms, Eve tells Carolyn that she doesn't like Konstantin.
Eve, Konstantin, and Carolyn arrive in the interview room. Konstantin leaves them alone, saying it is better if it is just them. Nadia enters on crutches and with a broken arm. Carolyn begins questioning Nadia, offering her release from prison and transport to the UK. Eve asks about Oksana and Nadia reveals that Oksana took her place in their plan to escape the prison. Konstantin walks through the door, interrupting Nadia's story about what happened three years prior. He claims the sound in the other room wasn't working but Nadia refuses to speak further on the escape plan. She mentions the name "Anna" and Konstantin commands her to tell them.
Vladimir meets up with Konstantin, Carolyn, and Eve in a car. Carolyn asks Vladimir to grant immunity and safe passage for Nadia so they can get further information. Vlad wants to know the name of the organization behind the assassinations and Eve tells him it is the Twelve. Vlad still refuses to help and exits the car.
Carolyn and Eve are at the bar, drinking. Eve tells Carolyn that she doesn't like Vlad, either. Carolyn reveals that she and Vlad have an "illicit" history together, however, Vlad still has not forgiven her for a plutonium plot he was framed for when it had been Konstantin who was Carolyn's source. Eve apologizes for not liking either of Carolyn's "boyfriends." After Carolyn heads to bed, Eve calls Kenny to see what he found out about Anna. Kenny tells her that Anna was the wife of the man Villanelle had castrated six years previously. Eve asks Kenny to dig up any information on Konstantin and Carolyn.
Eve calls Kenny, begging for any private information he can find between Konstantin and Carolyn. Kenny calls Eve back that he found letters from Konstantin.
Carolyn returns to the Hotel Atlasov in Moscow after being gone all night and wearing the same clothes as the day before. She runs into Eve and tells her that Vlad had a change of heart and will be giving them Nadia. Carolyn receives a phone call alerting them that Nadia was murdered. Konstantin joins Eve and Carolyn for breakfast and explains that Nadia was attacked by another inmate, "Natalie." Eve wants to meet "Natalie" but Konstantin laughs and refuses. Konstantin takes his leave, telling them they can stay but they're no longer invited.
As Eve and Carolyn walk the streets of Moscow, Carolyn reveals that Kenny is now in Moscow. They arrive at a shop and are allowed into a backroom where Kenny has set up a temporary office. At their new office, Eve tries to get the heat to work as she hypothesizes that "Natalie" is actually Villanelle. Kenny volunteers to check CCTV for visitors but Carolyn shuts him down. Eve changes tactics and decides they must find Anna. Carolyn says it is unnecessary and asks Kenny to have Elena fly them back to London since there is nothing left for them in Moscow. Carolyn will remain behind to "tie up" some things.
After Carolyn leaves, Eve and Kenny decide to remain in Moscow anyway and Kenny presents Eve with some personal letters of his mother's that he found. The letters are dated from 1977-1978 and are of an explicit nature. Eve is planning to give them to Vlad as proof that he was not the one involved in the plutonium plot but asks Kenny to go through them to see if there might be a code. Kenny also found some old photos, one of which has Konstantin sitting with Carolyn.
Eve enters their temporary office and joins Kenny to search through the prison CCTV footage. Eve spots a prisoner from behind that walks like Villanelle. Kenny finds another angle and they zoom in on Villanelle's face, confirming that Villanelle was in the prison with Nadia. On the CCTV, Villanelle is led into a visitor's room where Carolyn shows up to meet with her.
Eve wants to confront Carolyn about meeting with Villanelle in prison but Kenny is scared of Carolyn. They arrive at Carolyn's hotel and Eve convinces the front desk to give her a key to Carolyn's room. They find Carolyn's room a mess and Konstantin standing with a hair dryer. Carolyn exits from the bathroom and stops short when she sees Eve and Kenny. Eve states that Villanelle is in the prison. Carolyn explains that she escaped, locked Konstantin's wife in a cupboard, and kidnapped his daughter.
At breakfast, Carolyn tries to send Kenny away but he asks why Konstantin's security isn't looking for Villanelle and Irina. Konstantin reveals that the Twelve want him dead. Eve thinks they should go back to Anna's and calls her. Konstantin decides to go with Eve to Anna's and they will bring her back to the hotel. Carolyn sends Kenny to pack up their equipment, threatening to fire him if he refuses, while she is going to visit Vlad to set up protection for Anna.
At the airport, Carolyn informs Eve and Kenny that Konstantin has died. Eve checks her voicemail and hears a message from Elena that a young man (Sebastian) was found dead at an apartment in Paris with the same chemical in his system that killed Carla De Mann. Elena has uncovered that one of the apartments is paid for by the same account that was paying off Frank. Eve lies to Carolyn and tells her it was Niko on the phone. Carolyn confronts them about giving Vlad her love letters to Konstantin and fires them both. Carolyn and Kenny board the flight to London but Eve takes off in another direction.