Kai Parker

Malachi "Kai" Parker is the main antagonist of season six of The Vampire Diaries. He is a young warlock with the unnatural power to siphon magic. It is this power, and the fact he murdered his siblings, Kai was considered an abomination. Kai is out to kill his family and the Gemini Coven, all while becoming more powerful.

He is played by Chris Wood.

Past
Kai Parker was born to the Gemini Witch coven, along with his twin sister Joesette. The Gemini's can only survive with a leader, and they pick their leaders with a merge ritual; in which twins ritualistically fuse their magic, one of them dies (but their soul gets fused with the winner) and the other becomes more powerful in addition to being the leader. Because of Kai's siphoning power, he had an unfair advantage, so his parents kept having children until another set of twins, Luke and Liv, where born.

Angry at being denied his destiny, Kai goes on a murderous rampage killing his other siblings until it was down to him, Jo, Luke and Liv. When Kai corners Luke and Liv in their bedroom, Jo comes to their rescue, agreeing to do the merge ritual with Kai. This turns out to be a ruse to get the other Gemini's to trap him in a prison world. In said prison world, Kai lived the same day in 1994 in a desolated world.

Present
Following their deaths in season five's finale, Damon and Bonnie find themselves in Kai's prison world, living in an alternate Mystic Falls, where Kai eventually meets up with them. Almost immediately showing his true colors, constantly fighting them and tormenting them until its revealed that they are eachothers only hope of escape. With Bonnie's help, Kai makes it clear he intends to resume his murder spree. Bonnie opens a gateway back to the real world, and pushes Damon through, leaving her and Kai behind.

Damon meets up with his friends, Elena, Stefan, Caroline, Tyler and Matt, enlisting their help to save Bonnie. When the gateway is opened again, Kai makes his way through, leaving Bonnie behind. By coincidence, Damon's best friend Alaric, is dating Jo, and Liv has fallen for Tyler. Kai makes his way to Luke and Liv's college where he tries to kill Liv but is fought off by Tyler. Kai is also reunited with Damon and Elena, when they fight and Kai is knocked into Mystic Falls, which vampires are restricted from due to the Travelers spell. Kai taunts them by saying he will kill off the residents of Mystic Falls. After getting Jo, Luke and Liv together and attempts to force a merge ritual, but Damon and Alaric come to their rescue and Kai is knocked out in the fight. Kai is chained up just outside the anti magic border of Mystic Falls, but empowers himself by siphoning the Travelers leftover magic.

Now that vampires can enter Mystic Falls again and Kai is more powerful than ever, Kai kidnaps Elena and tests his new power by torturing Elena. Kai explains he tried on humans, but he ended up killing them. Elena tries to get through to Kai, but he proves he has no limits, remorse or empathy. Damon and Jo come to Elena's rescue and they fight Kai, and Kai is knocked out and put into a medically induced coma. When the Parker family father, Joshua arrives in Mystic Falls to force Luke and Liv into the merge before it's too late. Kai awakens and attempts to force Jo into a merge, but Luke arrives exploiting a loophole, and merges with Kai himself. Luke dies and Kai comes out victorious.

As a result of the merge, Luke's soul merges with Kai's, Kai begins to feel his brother emotions. Kai begins to feel the alien feeling of empathy and remorse. Damon and Elena use these to get him to help save Bonnie. Bonnie has ended up in another prison world, inhabited by the Salvatore's mother Lilly and the Hetric; vampire witch hybrids. Jo also discovers she is pregnant with Alaric's twins, and he asks Jo to marry him When Bonnie is saved, they travel back to that world to free Lilly, but a vengeful Bonnie leaves Kai behind.

In the prison world, Kai is turned into a Hetric and helps them escape into the real world. Having gotten over his feelings of remorse, Kai seeks out revenge and to complete his transformation. Kai attacks Jo and Alaric's wedding, stabbing Jo in the stomach, killing her and her unborn babies. Joshua and Damon try to fight him, but Kai causes the windows of the church to impolde and drop a chandelier. Elena is knocked unconscious and put into a magically induced coma. Kai kills himself to complete his transformation. Later Kai confronts Tyler and Alaric, and Tyler being a werewolf, bites Kai. Kai also attempts to kill Bonnie and confronts Damon, revealing that Elena's coma is magically linked to Bonnie's life and that she can only be awaken by Bonnie's death. Damon seemingly leaves Bonnie to her fate, only to immediately return and decapitate Kai.

Personality
Kai is an openly sadistic warlock, despite a thinly veiled façade of charm. Kai is openly unrepentant proud of how evil he is. Not only is he eager to continue murdering, he also isn't above killing children, as seen when he attempts to murder Luke and Liv as kids, and when he kills his pregnant twin sister by stabbing her stomach. Kai is remorseless and apathetic to his victims, openly gloating about being a mass murderer. At one point he may have cared for one of his brothers, but he immediately jokes that its in the past saying that one of his favorite memories was beating him to death. Kai notes that he enjoys being a sociopath as it gives him freedom of limiting emotions.

When his brothers soul merged with his, Kai began to feel artificial empathy and remorse. While he finds it to be an alien concept, he was mostly annoyed at it if anything. Kai initially tries to make up for what he did, not out of genuine remorse, but simply because he thought it would make the guilt go away. By the time he becomes a Hetric, Kai gets over his emotions and resumes his true goal to murder with complete impuity.

Trivia

 * Accoreding to Julie Plec and Caroline Dries, Kai is irredeemable. Despite this, Kai has a positive fan following.
 * Due to Kai's unrepentant viciousness and utter joy in killing, and is shown to kill children, Kai is considered one of the most evil villains in the Vampire Diaries universe, even more so than Klaus Mikaelson.
 * Kai has a slight similarity to Walder Frey of Game of Thrones; both are Complete Monsters, both are responsible for a massacre at a wedding, and both massacres start with the murder of a pregnant woman.
 * Kai is similar to Chase Collins of The Covenant. Both are Complete Monsters, both are teenage sadistic warlocks, both have murdered their families and both seek to further empower themselves.