Bonnie and Kai

The relationship between the witches Bonnie Bennett and Kai Parker.

They first met during Welcome to Paradise, after Kai attempts to kill Damon in order to reawaken Bonnie's magic.

Season 6
Bonnie first meets Kai in Welcome to Paradise when he attempts to kill Damon. She threatens him but he immediately mentions her inability to practice magic and proceeds to stake Damon. Just then, Bonnie's powers return when she lights a candle and she surrounds Kai with a wall of fire. Damon uses this to knock him out. Later on, they watch on as he wakes up and questions him on why he tried to kill Damon. He finally reveals that he only did it to ensure that Bonnie would get magic back.

In Black Hole Sun, Bonnie, unlike Damon seems more comfortable around Kai, even releasing him despite Damon's orders not to. After Kai convinces Damon to talk about his life in 1994, Bonnie is shocked to discover that he killed a pregnant woman.

Later on, Bonnie and Kai are seen trying to locate the Ascendant, though Bonnie is unable to do it, claiming that she doesn't feel comfortable. Damon immediately insults her by saying she sucks at magic which is when Kai jumps in, claiming that Bonnie should just ignore Damon. They flirt with each other for a few moments before Damon interrupts them with another remark. Later on, Bonnie is confused when her spell starts leading her directly to Mystic Falls despite the Ascendant supposedly being in Oregon. As she realizes Kai has it, she places her hand on his chest and all of the candles flicker, confirming her suspicion. Kai then finally mentions that he just tried to see if Bonnie's magic was precise and then claims that they're ready to go home.

Later on, Kai is seen in the front yard, trying to determine the location of where to harness the eclipse's power. Bonnie immediately mentions how he shouldn't have wasted their time with the locator spell to which he replies that he just wanted to feel her hand on his chest. Bonnie and Damon bicker about him and then as the two men continue walking, Bonnie takes one of the folded newspapers and remembers Kai mentioning something about having many sisters and brothers. This she connects to the family massacre explained in the newspapers. It turns out that Kai's real name is Malachai and that he is actually a witch, a powerless one as well as the murderer of his own siblings, much to Damon and Bonnie's shock. Bonnie immediately refuses to do the spell despite Damon's pleading. Kai is upset by this turn of events and tries to grab Bonnie, only to get attacked by Damon who was defending her. Later on, Damon and Bonnie plan on how to get back without Kai when he shows up, claiming that his special ability is to consume a witch's magic temporarily, though to the point of their death. He demonstrates this when he grabs Bonnie and channels her magic by setting the stove on fire and giving Damon an aneurysm while at the same time keeping Bonnie in a lot of pain due to using her magic. He then explains that if they don't all work together, he'll drain Bonnie's magic, kill her, and then do the same to Damon. The other option is for them all to go back together as allies and friends. In The World Has Turned and Left Me Here, Bonnie and Damon are walking through the woods to meet up with Kai, while they discuss him and his intentions. He quickly shows up and Bonnie asks him to show her the spell, though he refuses and heads off to gather some supplies. After returning, Bonnie refuses to do the spell until he actually shows it to her, though he refuses to show her the spell. The two eye each other angrily for a few moments until Bonnie finally challenges him to just absorb all of her magic and kill her as she won't do the spell. Kai at first is hesitant, but then grabs her and starts draining her magic painfully, with Bonnie fighting back. After some time though, he releases her and she then realizes he can't kill her because he doesn't know the spell. She figures that they don't need him and telekinetically shoves a pickaxe into his chest, killing him. After figuring out that she is the key to getting back, Bonnie and Damon prepare to return, but then Kai shows up and quickly shoots with an arrow to stop her. While he and Damon fight, Bonnie uses her magic and sends Kai a few yards back. She then proceeds to send Damon back to the mortal plane, while sacrificing her chance of getting back. The Ascendant is destroyed in the process and Kai angrily screams, realizing he is stuck there,possibly forever. Meanwhile, Bonnie cries, happy for Damon but sad for herself and then passes out from the bleeding wound, while now trapped with an enraged Kai in the time dimension.

In Do You Remember the First Time?, Kai has taken Bonnie back to the Salvatore Boarding House and has treated her wound. He is then seen trying to fix the Ascendant while Bonnie's lying on the couch, unconscious. After she finally wakes up, he asks her if she's okay and then assumes she's going to help him with fixing the Ascendant. She however refuses which forces Kai to demonstrate his power over her by grabbing her hand and so he starts draining her of her magic. Bonnie however grabs a pen from the table and stabs him in the neck which kills him temporarily. She then proceeds to get all of the parts of the Ascendant and runs out, with Kai dead on the floor. Bonnie eventually reaches the hospital where she treats her wound and manages to fix the Ascendant, only to realize she's missing one piece. Suddenly, all of the lights shut down and Kai appears with the last piece. As he slowly moves towards her, Bonnie reacts by destroying all of the objects around him which slows him down. She then runs back to Damon's car only to be unable to start the engine. Kai shows up in the backseat and grabs her from behind. She tries to fight back but is unable to and Kai forces her into getting them home.

They're later seen in the cave, awaiting the eclipse. Kai then reveals that he's brought her a "gift" - Mrs.Cuddles, thinking she wants to bring her childhood toy along. He then starts talking about how he wants to be a better man -- patient, loyal, and good -- like Bonnie. Bonnie cuts him off and says that they should just go home. He gives her the Ascendant and she starts performing the spell. As he grabs her hand, she lets a little of her blood fall onto her teddy bear. Suddenly though, she stops the spell, claiming she's lost her magic. Kai then grabs Bonnie only to realize there's no magic left in her. He then tries to figure out what happened, only for Bonnie to reveal that she placed all of her magic somewhere safe.

Kai realizes it's in the bear though then finds out that it was sent back to the mortal plane. He starts yelling to which Bonnie responds by provoking him even more as she says that they're stuck there forever.

In Fade Into You, Kai kidnaps Bonnie by drugging her with pain killers. He then takes them both to Portland, Oregon, to his family home. He drags Bonnie out of the trunk and she starts wondering where they are. After he cuts the rope around her hands, he reveals to her they're in Portland, and she starts complaining, claiming he could have taken her anywhere in the world yet he took her to Portland. He claims it's Thanksgiving in the real world & that he's gonna make Bonnie dinner.

As they near his house, Bonnie questions him on why he wanted to come here, to which he responds by saying he wanted to finally show his house to someone. They're later both seen in the kitchen, with Kai making them dinner while Bonnie plays with his pager, though he quickly takes it from her, claiming he doesn't want her to bust it. Bonnie then finally mentions how she doesn't want to spend the rest of eternity with him, claiming she will never like him or enjoy his company, though he claims he wants to apologize for everything. She however claims they should divide the world in two and separate. Kai finally accepts the deal, claiming he'll even give Bonnie his car, though only if she has one last dinner with him. She happily accepts. They're later seen eating, with Bonnie boringly starring at Kai as he eats the same piece for 45 minutes. She tells him to quit stalling & give her his car keys though he continues stalling by telling Bonnie who actually sent him to the prison world they're in - his father. They then finally walk outside, with Kai explaining the events of the night he was banished. They walk over to a tree stump and Kai finds the knife his sister imbued with her magic, still there. He drains the knife of Jo's magic and reveals how he needs Bonnie's blood for the spell. He then quickly stabs Bonnie and leaves her there, lying on the grass. Bonnie later on wakes up, realizing he lied to her about letting her go peacefully & giving her his car.

Trivia

 * They are both witches, although Kai does not have his own magic unlike Bonnie.
 * Bonnie was the first witch in more than 18 years to fall victim to Kai's magic-draining powers, though he did not drain her power completely, instead he only did so as a demonstration of his abnormal power.
 * Kai was the one who caused Bonnie's magic to awaken by threatening to kill Damon.
 * They have both acted against their own kind and killed another witch; Kai slaughtered his entire family of witches (for no apparent reason) while Bonnie killed Kai and has tried to kill a coven of witches while under Silas' control.
 * Both have attacked each other; Bonnie stabbed Kai with a pickaxe and later on, he shot her with an arrow. He also later on stabs Bonnie in order to use her Bennett blood.
 * As of The World Has Turned and Left Me Here, Bonnie is trapped with Kai in the Otherworldly Time Dimension, with no way out as the Ascendant was broken when Bonnie sent Damon back. Bonnie fixed the Ascendant in Do You Remember the First Time, but she stored her magic in her childhood teddy bear, Mrs. Cuddles, so that neither she or Kai could leave.
 * In Fade Into You, Kai stabs & leaves Bonnie alone in the Prison World, using her blood to return the mortal plane. He leaves her there as revenge for her sending her magic away.
 * In The Day I Tried To Live, Kai helps Elena, Damon, and Jeremy to bring Bonnie back.