"This one grew up in all the right places. I don't know whether to kill it or ... lick it." - Kate about Derek Hale
"You know how every family has its secrets? Ours are a little different." - Kate to Allison Argent
"So my question is simple. What the hell ... is so special ... about Scott McCall?" - Kate to Scott McCall
Kate Argent is Allison Argent's aunt, Chris Argent's sister and a member of the Argent clan of hunters. Prior to the series, Kate orchestrated the Hale House fire, burning the Hales' pack and family alive, murdering innocent werewolves, including children and human members, breaking the Hunter's code. In Season 1, Kate arrives in Beacon Hills, accompanies her family in hunting Peter Hale, a lethal Alpha werewolf. She lures Allison into discovering the supernatural and manipulates her into hunting Derek Hale and Scott McCall planning to kill them, but her role in the arson is exposed. Kate is then killed by Peter Hale in revenge for massacring his family. The transformation however, is set in motion by Peter's claws, and so Kate gradually comes back to life as a new werejaguar. She then becomes a quarry of the Calavera family, then takes control of two berserkers. In Season 4, Kate uses her berserkers to assault Scott's Pack, tracks the Benefactor and accepts a deal with Peter to have Scott killed in petty vengeance for the disbanding of her family and Allison's death. She transforms Scott into a new berserker to have him kill his friends and vice versa to this end, but Peter intends to betray her. Scott's pack and allies launch an all out attack against Kate, then she is defeated by Derek and Chris, her berserkers are destroyed and the plan fails, so Kate goes on the run.
Kate is portrayed as sassy, vivacious and has a carefree, sultry swagger to her. She behaves more like an older sister than an authority figure to her niece, Allison.
As a result of her racist upbringing and training in the Argent family, under her cold-hearted father, Gerard, Kate is tough and fearless, but also extremely sadistic and psychopathic. A trained hunter, she is immensely bloodthirsty, deadly and cruel. She takes great pleasure in hunting, torturing, and killing any werecreature she comes across without restraint, whether or not they were innocent. She is remorseless over her crimes, and revels in the carnage she's committed. Kate shares Gerard's view that all supernaturals should be just put down.
"I did what I was told to do."
"No one asked you to murder innocent people ... children ... ones who were human. You're holding a gun at a sixteen-year-old boy. With no proof he spilled human blood!!" - Kate and Chris
Like her father Gerard, Kate is a selfish manipulator, willing to use her family, Allison her niece, so to use for her own needs.
Being rife with sexual innuendo, Kate is also a ephebophile, willing to use her charm and sexuality to her advantage, having seduced Derek Hale while he was a teenager in her intention to use him so to get close to his family.
Kate seduced Derek, luring him into a physical relationship. In doing so, she gathered intel on the Hales. Later on, with a number of hired hands, Kate set fire to the Hale House, murdering most of Derek's family and got away with it.
Kate wanted Allison to know her family's history and crusade. When the Alpha Werewolf began murdering people back in Beacon Hills, Kate, hoping to cover up any probable evidence connecting her to the fire, called her brother and came into town.
Kate arrives in Beacon Hills. She listens to a local news report discussing the recent line of Beacon Hills' 'animal attacks'. She scoffs at the news then switches the radio to a music channel. She doesn't know the Beacon Hills Alpha is tracking her, chasing her with Wolf speed.
Kate stops at a stop sign. Suddenly the werewolf lands on the roof of her car, startling her. The Wolf smashes through the car window, reaches its clawed hand through and attempts to snatch her.
Kate: "Come on!" (Fires off a shot.) "COME ON!"
After the Alpha retreats, Kate takes an assault rifle out of her car's back compartment. She loads the weapon with wolfsbane bullets, takes out a flashlight and calls in her brother for assistance. Scouting the area, she spots a werewolf taking to the rooftops, takes aim and shoots him with a special bullet, giving herself a satisfied smile. Kate then greets her brother who's just arrived. Chris scolds her that one of local werewolves is going to lead them to the Alpha and won't be able do that if he's dead. Kate responds she can't help stop them if one of them kills her first. She estimates the bullet she fired will give her victim 48 hours.
The following morning, Kate and Allison greet each other enthusiastically after not seeing each other for a year. Kate remarks that Allison now looks like a runaway model and she'll have boys lining up soon enough. Allison tells her she already has one.
Chris tries to send Scott home, but Kate instead invites him to a family dinner with the Argents, noting on his adorable brown eyes.
Throughout the evening, she teases Scott whilst Chris persistently grilling him.
She catches Scott while he's "going to the bathroom" and encourages him to use the one joining her guest bedroom.
Once Scott is just leaving, Kate accuses Scott of taking something from her bag. Scott swears he didn'ttake anything. Kate asks if he could prove that by turning out his pockets. But Allison confesses to taking a condom. Everyone is stunned.
Kate converses with Chris about the werewolves. She recalls the one she shot was lean and fast, but the one who jumped on top of her car was huge and powerful. Chris identifies the former as Derek Hale. Kate asks are they sure there's only two of them in town. Chris answers they're not yet sure.
Kate, amused, lights a fire remembering the Hale Fire.
Kate: "Of course. I always play by the rules."
Kate shows her the symbol in the middle of the pendant, and asks does Allison ever want to learn a little something about her family, wanting Allison to start looking into the family's covert activities and join their supernatural business. Allison again thanks Kate for the gift and heads for school.
Chris wants the hunters to remain in the shadows and urges restraint whilst they gather more information. Kate however is impatient.
She leads them into the house which appears deserted. She lures Derek out of hiding using the death of his sister.
Kate: "Too bad your sister bit it, before she had her first litter. Too bad she howled like a bitch ... WHEN WE CUT HER IN HALF!"
Derek roars in rage and knocks out the two men. He glowers at Kate, fangs bared, incensed at seeing her again, and Kate sadistically smirks back. She gleefully invites the werewolf to attack, whipping out a taser. Derek impulsively goes on the attack, but she gets the better of him, shocking Derek, incapacitating him.
Kate remarks that Derek grew up "in all the right places," admiring his physique. The sadistic huntress then fanatically tortures him with her taser, taking pleasure in watching his agony.
Derek, recovering, glares back at her. Kate surmises he thinks that she's lying to him. Derek snarls at her, "Wouldn't be the first time."
Kate offers that Derek listen to her say the words again and listen to her heartbeat to see if she's lying and repeats her words that they didn't kill Laura. The Alpha did. Derek absorbs this. Kate offers to kill the Alpha for him and the problem is solved. She realizes Derek doesn't know who the Alpha is. Declaring him useless and with no witnesses, she decides to kill him, but Derek evades her gunfire, running out into the woods.
When Allison mentions about needing a subject for her history assignment. Kate recommends something. She directs Allison to the legend of La bete du Gevaudan on her niece's computer, giving Allison another clue to their family legacy, wanting her to join the family's supernatural business. A wolf-like creature was preying upon and terrorizing the French province of Gevaudan, killing scores of people until it was finally killed by someone who's name was Argent.
Kate is then seen with Chris and two of their own, Ulfrich and Tyhurst, a state detective, as they gear up for a hunt as tonight is a full moon. At first, everyone assumes the Alpha won't have a target because of the new moon and he would lose control under its sway. Kate however, starts thinking and asks what if the werewolf has a reason to stay focused, covering up her assertion that she doesn't like surprises.
Kate however learns of Scott's connection to Derek after Allison mentions she saw them together at school. Suspicious, Kate urges Allison to tell her everything she knows about Scott regarding Derek.
Chris and Kate observe the latest murder by the Alpha and see Stiles, another of Allison's friends at the scene. Kate brings up the possibility with Chris that the second Beta he saw the last full moon could be a student and also informs Chris of Scott knowing Derek Hale.
A couple of weeks later, the hunters follow the police chasing after Derek Hale at night. Kate and Chris are involved in the chase and Kate trails Derek's car. Chris reports Derek is running into the ironworks. Kate asks who's driving Derek's car then. Derek manages to evade the police and the hunters.
Kate follows Allison when she goes out on her annual morning run through the woods. Allison heads into the deserted Hale House to investigate. Kate comes up on Allison surprising her. Kate explains herself that she can't be blamed for "being concerned about her favourite niece."
Kate: "You don't have to be psychotic to be a killer. You just ... need a reason. And even then sometimes, you can surprise yourself."
Kate asks Allison what does she want. Allison rants that she wants to not be scared, she wants to feel stronger, to be able to protect herself. Pleased with Allison's answer, Kate tells her to be patient and she might be able to get her what she wants.
At the high school lacrosse game, Chris, Kate and Allison are in attendence. After Allison points out Jackson to Kate, Kate responds positively to his looks and teases Allison should be all over him. Kate notices the claw marks on the nape of Jackson's neck. She whispers to Chris could someone be turned into a werewolf by a scratch and converses the possibility with him that Jackson is the second beta.
Late at night, Kate and Chris come back home, after practising the hunter's trade and skills. Kate remarks that setting off their flashbangs so close to civilization is bound to draw them some attention. Her brother answers her he knows when to be conspicuous when he needs to. Kate enquires that they should be teaching Allison their skills, in light of recent events. Chris insists Allison's time isn't yet to come.
At the high school, Kate is tracking Jackson Whittemore. She witnesses him following Derek Hale out of the school.
Later, Kate sends Allison a text, telling her to meet with her saying they neded to talk. Allison meets up with her. Kate takes Allison to an underground dungeon. Allison is perplexed, asking Kate where are they. Kate resonds with 'the basics'. She tells her niece that every family has secrets, but their own are a little different, showing Allison into a darkened chamber.
Kate: Isn't he beautiful?
Kate turns on the device wired up to Derek to electrocute him, torture him in front of a horrified Allison. Kate shows off Derek's supernatural attributes to Allison to have her niece believe the existence of shapeshifters and share Kate's own monstrous views towards them attempting to pull her niece towards her way of thinking. Allison is appalled at her aunt's obvious sadistic tendencies. Kate responds "Everything's a joke to (herself)."
Kate tells Allison to go back to school, be a normal teenage girl and prepare for the formal before the next part. Kate reminds Allison that she said she wanted to be stronger and she's going to get to do that by helping Kate catch the second Beta.
Kate returns to the chamber to personally torture Derek for her own pleasure and for information. She carries out her torture with an associate, Marcus, but Chris is unaware of her actions. She interrogates him for the identities of the second Beta and the Alpha.
Kate: "I love how much you hate me."
After a day of keeping Derek prisoner and he steadfastedly refuses to give up, and with Chris starting to get suspicious, Kate decides to just kill Derek. She realizes Derek never told anybody about their affair incluing his sister. She takes wicked pleasure in his showing guilt and torment. She amusedly tells the werewolf he got tricked "by a pretty face", a werewolf who falls for a beautiful girl from a family who kills the werewolves. She follows up with the surmisation that maybe history would be repeating itself where he would be inadvertently helping her track down then the rest of the Pack. It'll be history repeating itself, which gets stuck in her head. She realizes the second beta isn't Jackson Whittemore, because Jackson isn't in love with Allison, Scott is the second beta.
Chris and Allison return home at the Argents' residence and it comes out Allison also knows everything about their family. Chris is furious, partially at Kate for revealing everything to Allison against his wishes. Kate snarks, trying to play innocent that Allison found out herslef. Chris yells that he knows about the clues she's been leaving her. Kate fires back that Allison needs to know.
Chris decisively says he's aware, so Kate is taking Allison out of town to the safehouse in Washington. Kate amusedly complains that she's going to be benched, but Chris gets in her face and teels her he wants she and Allison on the road within the hour, leaving no room for arguement.
Kate isn't planning on leaving town, however. She and a silent Allison are in the car when Chris comes out to see them off. Kate insists he's not going to find the Alpha without her, but Chris just sends them off.
Kate: "Do you get that now? It's what they do. And they can't help it."
Allison: "All of them?"
Kate: "Yes, Allison. Even Scott."
With a groomed and furious Allison completely at her disposal, Kate has the two of them gear up and head to the Hale House.
Lateron, the two easily catch both Scott and Derek in their sights. Kate coaches Allison who then puts arrows in Derek in the chest and leg and blinds Scott with a flashbang. They walk up to the two disabled werewolves.
Kate: "I love those brown eyes."
Before she pulls the trigger, Chris' yell comes out of the night, stalling her. Chris has arrived and disgustedly confronts Kate, telling her he knows what she did, that she orchestrated the Hale Fire and orders her to lower her gun. Kate justifies she did what "(she) was told to do", but Chris points out all her crimes, now including threatening a sixteen-year-old, that she has broke the code to her annoyance. She just aims her gun at Scott, but Chris pulls his gun on her, again ordering her to put hers down. He fires a warning shot over her arm. Kate, astounded, finally obeys.
Kate covers all her bases with her gun drawn. She impatiently calls out to the werewolf. Suddenly, she is caught in a painful iron-clad grip by the alpha, Peter Hale.
He breaks her arm, causing her to drop her firearm and drags her painfully into the Hale House, about to exact his revenge on her for the Fire, having overheard the previous exchange.
Peter: "Apologize. Say that you're sorry for decimating my family. For leaving me burned and broken for six years. Say it. And I'll let her live.
Kate stammers and looks at a terrified and devastated Allison.
Kate: "I'm sorry."
After Peter is killed, Chris leaves the Argent pendant on Kate's corpse so the police will uncover her part in the fire and pin the murders on her. Sheriff Noah Stilinski finds Kate's corpse and the necklace and the case is closed.
In Season 3, Kate returns as a vision that haunts Allison after she sacrificed herself to the nemeton. She first appears in 3x13 - Anchors, clawing her way out of the freezer in the morgue that bears her name.
At the end of Season 3, Mexican hunters break into Derek's loft in their hunt for La Loba. They are suddenly attacked, and then Derek is shot in the chest. He's so terrified by what he sees that he briefly hallucinates a conversation with Stiles, then comes back to the present to see that Kate is alive.
The Calavera's reveal that they took Kate after Peter "killed" her because they heard she had been slashed by an alphas claws. They switched out her body so the Argents buried someone else. They locked Kate up and expected her to kill herself, but instead she pretended to slash her wrists and then killed six hunters to escape. In present time, she has sealed Derek inside a temple to Tezcatlipoca.
Kate has trouble control her new ablilities; which leads to the death of a gas station attendent. She gets a now younger Derek to take her to his family's vault. She believes that there is something in the vault that will help her to control her shifting.
A flashback of four weeks ago shows Kate listening to a mixtape explaining the Hale's Triskelion. When she finds out that the tape lied about the Triskelion, Kate goes in search for The Benefactor. She kills numerous assassins seeking information. She fights her brother, Chris but doesn't let the berserkers kill him. At the end of the episode Peter comes to her and offers to teach her control.
Kate tests out berserker Scott's loyalty by having him attack Kira. She takes on Chris and a group of the Calavera hunters. She is finally beaten by Derek, who had just transformed into a full wolf. She is shot with a wolfsbane bullet by Chris. However, Kate manages to escape.