“You should never tell a psychopath they are a psychopath. It upsets them.” That’s just one of the many juicy lines that slide out of the mouth of Villanelle, one of the most mystifying, stylish, and fascinating characters on television. It’s been two long years since we spent some dangerous quality time with the killer dynamic duo that is Villanelle and Eve, two women that, no matter how hard they try (or pretend to try), can’t quite seem to shake each other. Based on the serial novella by Luke Jennings and developed for the screen by Phoebe Waller-Bridge, Killing Eve follows MI5 analyst Eve Polastri (Sandra Oh) who gets sucked into an unsolved case involving expert assassin Villanelle (Jodie Comer). Eve is hired by the secretive MI6 division leader Carolyn Martens (Fiona Shaw) to identify patterns in the worldly assassin’s behavior and put an end to her high-profile killings.

Eve abandons all of her responsibilities outside of work, and both her and Villanelle become obsessed with tracking each other down. As the series progresses, Villanelle and Eve’s connection (and chemistry) becomes so strong that they realize they might not be able to live without the other. The series has been nominated for 19 Emmys, including Outstanding Drama Series and for its writing, and acting in Oh, Comer (who won), and Shaw. The final season will welcome back old friends and invite new faces along for one more thrilling ride.

Let’s get to know the dangerously fun folks that will be taking over our screens for Season 4 of Killing Eve.

Editor’s note: The following contains spoilers through the Season 3 finale of Killing Eve.

Villanelle/Oksana (Jodie Comer)

Image via BBC America

One of the two leads of Killing Eve is Villanelle, the witty, stylish, and sarcastic stealth assassin who has some major attachment issues. Though she was born as Oksana, she’s been trained from a young age to be a ruthless killer and now goes by the name Villanelle. She quickly becomes obsessed with Eve Polastri, the MI6 agent trying to track her down, which leads the both of them into a number of life-threatening and unexpected circumstances. Last season proved to be Villanelle’s most painful season yet, as she confronted her past, was crippled by the present, and tried to create a more stable future. Let’s not forget that she unexpectedly got married (for like, a minute) and ignited one heck of a fiery family reunion.

While she’s likely best known for her Emmy-winning performance as Villanelle, Jodie Comer has appeared in a number of British and American projects. She starred in three critically acclaimed series: My Mad Fat Diary, Thirteen, and Doctor Foster: A Woman Second and recently shined alongside Ryan Reynolds in the hit film Free Guy and in Ridley Scott’s period epic The Last Duel. She’ll be making her West End debut in Suzie Miller’s play Prima Facie in the Spring of this year.

Eve Polastri (Sandra Oh)

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Image via BBC America

Oh Eve, you naive, determined soul. When we first meet Eve, she's somewhat out-of-place in a meeting with her fellow MI5 colleagues. (She's more focused on her croissant than she is the tasks at hand.) But when she learns about a string of hits from a mysterious and elusive assassin, her ears perk up. Not only does she think that the crew should pay more attention to the killer, she’s certain it’s a female. In a whirlwind of events, she gets fired from her job and hired by MI6 leader Carolyn Martens to further investigate the infamous case. This marks the beginning of an unpredictable journey of death, heartache, undeniable chemistry, and a whole lot of mixed feelings.

Sandra Oh is a 12-time Emmy nominated actress known for her work on the long-running series Grey’s Anatomy and the recent Netflix limited series The Chair with Jay Duplass and Holland Taylor. She’s the voice of Debbie Grayson in the hit Amazon Prime animated series Invincible and can next be heard in the upcoming film Turning Red, which is available on Disney+ March 11.

Carolyn Martens (Fiona Shaw)

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Image via BBC America

Carolyn Martens is the stiff-upper-lipped leader of MI6’s Russian section. When Eve expresses an interest and some fresh insight into the unknown assassin case, Carolyn recruits her to help track the assassin (Villanelle) down. Carolyn’s investigations often get herself, her co-workers, and loved ones in a lot of trouble because the missions are often run covertly and without official government permission. Though she seems to have a lot of ex-lovers, she has a cold persona and weak relationship with her children, Geraldine and Kenny, the latter of whom is…dead?

Fiona Shaw is known for playing Petunia Dursley in the Harry Potter films, as well as her work in Mrs. Wilson, True Blood, Ammonite, and Baptiste. She’s set to star in John Krasinski’s If with Steve Carell and Ryan Reynolds and Hot Milk with Jessie Buckley.

Konstantin Vasiliev (Kim Bodnia)

Konstantin

He’s got a laugh you can identify at even the loudest of parties. The lovable Konstantin has been through quite a lot as Villanelle’s handler and go-between for the Twelve. The dignified middle-man is actually quite the softy, which often causes more harm (and heart problems) than good in his line of work. Let’s not forget that when he’s not worrying about his unofficial daughter Villanelle, Konstantin is consumed with stress over the fact that his real daughter, the precocious and now lethal Irina (Yuli Lagodinsky) has spent way too much alone time with Villanelle. In fact, the wicked yet charming assassin has become a role model for little Irina, whose recent behavior had deadly consequences.

Actor Kim Bodnia had a recurring role in Netflix's The Witcher and The Letter for the King. He can next be seen in the upcoming crime thriller Nefarious.

RELATED: 'Killing Eve': Best Episodes to Watch Before the Final Season

Hélène (Camille Cottin)

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The Twelve’s boss just got a promotion. Actress Camille Cottin was upped to a series regular for the final season to continue her role as Villanelle’s boss. While the enigmatic Hélène has always supposedly been the master orchestrator of Villanelle and Konstatin’s missions, we don't formally meet her until Season 3. Villanelle loathes this woman and always tries to (literally) squirm out of her slithery grip, though it doesn’t seem like she’s going anywhere.

Cottin recently starred as interior designer Paola Franchi in House of Gucci and alongside Matt Damon in Tom McCarthy’s Stillwater. She’s also one of the leads in the hit French dramedy series Call My Agent!, which is available on Netflix.

Yusuf (Robert Gilbert)

Joining the cast as a series regular is actor Robert Gilbert as the “warm and charismatic” Yusuf, an ex-army man who works (very) closely with Eve on a revenge mission. Given some of the choice words in the trailer, it’s safe to say that Yusuf and Eve will have some sort of romantic involvement.

Gilbert is known for his work in Ready Player One, Star Trek: Lower Decks, and Joel Coen’s recent film The Tragedy of Macbeth.

Pam (Anja Vasan)

The second new series regular is actress Anja Vasan as Pam, an up-and-coming assassin with a bully for a brother. She views her work in the family funeral business as a much-needed respite from her troubled home life. Anja Vasan stars in the Peacock series We Are Lady Parts and can be seen as Sister Claire in the musical period film Cyrano starring Peter Dinklage.

Gunn (Marie-Sophie Ferdane)

The last of the trio of new characters is Gunn, an assassin described as being more complicated and having “even more issues than Villanelle,” which is…almost impossible. Though Killing Eve is ending, creators have been outspoken about the possibility of spin-offs. Perhaps we will be following Gunn’s misadventures as a killer in a different series? Actress Marie-Sophie Ferdane is known for her work in Netflix film I Am Not an Easy Man, the miniseries Savages, and as the lead in the French music thriller series Philharmonia.

The fourth and final exquisite season of Killing Eve premieres Sunday, February 27. Grab your tissues, folks.