|“||One stake, three of us. Even if you don't hesitate, the other two will rip you in half.||”|
Klaus first heard about his aunt from his older brother Finn Mikaelson in The Originals Season Two episode The Brothers That Care Forgot Finn told him about the firstborn curse placed on their family in order to justify their mother's attempt to take Klaus' daughter Hope's life - Klaus' mother preferred her only granddaughter die shortly after her birth than be raised as a magical slave at the hands of her great-aunt. Klaus, who was well aware of his mother's strong powers, realized that his aunt might just be even more dangerous in comparison. Klaus and his siblings spent the rest of the season trying to learn more about their aunt Dahlia, whom they knew little to nothing about. After a talk with his eldest sister Freya Mikaelson after she had reawakened from her century of sleep, Klaus and Elijah were able to gather useful information about their aunt, but the more they discovered, the more concerned they grew - realizing that Dahlia might be the most powerful witch they had ever faced.
A while after that, Dahlia came to New Orleans to take Hope. Klaus, of course looked for every way to kill his allegedly immortal aunt - even going as far as teaming up with Mikael. But after that failed, Dahlia attempted to separate him from his siblings, and succeeded, as she framed her nephew in the murder of Aiden - and Klaus took the blame on himself to keep Hayley from leaving New Orleans with Hope. As a result, Elijah eventually dagger him in front of their sisters. While daggered, Dahlia castes a spell to make a daggered Klaus see her past memories with Esther, and then with Freya. She convinced him to work together with her - he will raise Hope as her father, she will channel her power, be Hope's mentor, and be his ally - and nobody will ever dare challenge him. Klaus, unwilling to trust his aunt in anyway - declines. But after he realized that Hayley and her husband took his daughter, and his siblings agreed to it, he turns to her help.
After feeding, he and Dahlia stole the werewolf curse that Marcel owned, and as punishment for taking his daughter, Klaus have Dahlia put the curse on crescent wolf clan once again. But as Dahlia wished to link herself to Hope, it all turned up to be a ruse: Klaus never wished to be her ally, he just meant to learn more about her - in order to defeat her, and to use her to punish Hayley and the wolfs who took his child. Klaus daggers himself, and, as he is linked to Dahlia (he suggested that as a temporally alternative) - they both fall to ground. But even unconscious, Dahlia managed to melt the dagger, and almost killed Klaus, but Marcel saved him. After they revived Esther, Klaus killed her yet again - in order to use her blood to kill Dahlia, and finally; he succeeded.
Throughout The Originals Series
In Night Has A Thousand Eyes, Klaus met his aunt Dahlia for the first time when she arrived to New Orleans to claim his daughter, whom she believed was rightfully owed to her as a result of her bargain with Esther. He feared Dahlia taking his daughter so much that he later teamed up with Mikael, whom he loathed, to kill her and prevent their respective beloved daughters (Hope and Freya) from Dahlia's influence. Unfortunately, their plan, which involved a dagger bound with the three ingredients that they believed made up her sole weakness (Norwegian soil, ash of her Viking oppressors, and the blood of Freya, the only person who had broken her heart) failed when Dahlia found and destroyed the blade. Afterward, Dahlia assured them that her only intention was to claim what was owed to her, and that as long as she got it, she would leave peacefully, and then left them to lick their proverbial wounds. When they return to the compound, Freya and Mikael, who verbally attacked Klaus for rushing their plan to kill Dahlia, which led to the destruction of their sole weapon, Klaus killed Mikael in front of Elijah, Rebekah, and Freya in order to recollect the Viking ashes needed to create another weapon.
In When the Levee Breaks, Dahlia, after overhearing a conversation between the werewolves Aiden and Jackson in which Aiden confessed to having spied for Klaus, cornered Aiden in an alley and ripped out his heart with the intention of framing Klaus for his murder, believing that it would be the last straw to turn the Mikaelsons against each other. As she intended, Jackson, Hayley, and the Crescent wolves, along with Elijah, Rebekah, and Freya, assumed Klaus was guilty, especially when he himself falsely admitted to doing it in hopes that everyone would fear him enough to go along with his plan. However, it only succeeding in worrying everyone enough that Elijah used the golden dagger enchanted by Kol and Davina to incapacitate Klaus while they made a new plan to fight Dahlia.
In City Beneath The Sea, After Klaus was daggered by Elijah, Dahlia used her magic to bring his consciousness into her mind so she could show Klaus memories from her past that shaped who she grew up to be in order to demonstrate that they were much more alike than he wanted to admit. Among the memories she showed him were Esther abandoning her while they were in Viking captivity to marry Mikael and start a family to demonstrate that she, too, had been betrayed by the family she loved. She also showed him a memory of Freya from when she was just a young adult in the 11th century, and how difficult it was to learn to control her abilities due to her status as a firstborn witch of Esther and Dahlia's bloodline, who are known to possess devastating amounts of magical power. As part of her attempt to form an alliance with her nephew, Dahlia also revealed to Klaus the reason why it is important that Dahlia help in raising Hope - not only is Hope a firstborn witch of her bloodline, but she also has additional power from her vampire and werewolf heritage, and if she doesn't receive the proper training to learn to control her magic, she will not only destroy herself, but anyone around her. In order to avoid the mistakes she made with Freya, Dahlia also offers to allow Klaus to continue to raise Hope alongside her, so Hope can have her father in her life and not suffer the loneliness and abandonment that Freya experienced; however, she would agree to this only if Klaus killed Hayley, as she knew Hayley would never agree to allow Dahlia to raise her. Dahlia then gave Klaus the magical power necessary to overcome the effects of the dagger and remove it from his chest so he could fight at her side. When Klaus overheard Elijah and Rebekah listening to a voicemail from Hayley informing that she was leaving with Hope due to Klaus' erratic and reckless behavior, Klaus became so angry that he tracked down Dahlia and agreed to help her in exchange for her help in punishing Hayley.
In Fire with Fire, Klaus worked with Dahlia to dismantle his siblings' plans to kill her in order to gain his aunt's trust, which included; compelling Gia to kill herself in the sunlight in front of Elijah and stabbing him with Papa Tunde's blade; compelling Marcel to kill Rebekah if she tried to escape the compound, as killing her vessel would result in her spirit returning to her original body; and placing an adapted version of the Crescent Curse on Hayley, Jackson, and the rest of the Crescent wolves, which trapped them in their wolf forms at all times, save for the hours of the full moon. After finding Hope in the car after Mary, who was protecting her, was forced into her wolf form by the curse, Klaus stopped Dahlia from immediately linking herself to Hope by first convincing her to link herself to him; to convince her to do this, Klaus claimed that he didn't want to risk Hope being forced into the same pseudo-immortality curse that gave Dahlia invulnerability in exchange for being forced to sleep for a century and awaken for a single year of life before repeating the cycle anew.
In Ashes to Ashes, Klaus was successfully linked to Dahlia. He then turned the dagger Davina and Kol created onto himself, neutralizing both of them in the process. However, since the dagger was not made to neutralize her specifically, she was still conscious enough to use her magic to melt the dagger, and in doing so breaking the link between them, along with their alliance. She later nearly killed him and his Original vampire siblings by exploding the white oak stake and forcing them to inhale the particles, burning them from the inside. Fortunately for them, they are saved by their mother Esther, who trapped Dahlia with her chains, freeing Freya from being strangled just in time for her to cast a spell to reverse the properties of the stake particles. Klaus was then able to kill Dahlia by running both Esther and Dahlia through with the second enchanted blade made by Freya.
Klaus : "Well? What are you waiting for, you crone?"
Dahlia : "Now that you've arrived... not a thing!"
Klaus : "Let me guess, the Vikings slaughtered the entire village."
Dahlia : "Esther and I were the only ones who survived. We promised to stay together."
Klaus : "Yes, "always and forever." A familiar promise. But, then, you knew that. I suppose you think that makes us kindred spirits."
Dahlia : "Not exactly. What I mean to show you is that we can be allies."
Dahlia : "I performed the dark magic they demanded so that Esther would be free of their violent abuse. While she was out in the sun gathering herbs, I toiled in the gray of this room. But, I never resented her. We'd made a promise."
Klaus : "Very cliché. Tell me, did you inspire the witches of Grimm lore? Enslaving a young girl in a hut on the edge of a dark forest? I suppose you plan for this to be Hope's fate."
Dahlia : "I did not enslave Freya, I kept her from those who abuse our craft, demonized us... and, most importantly, I shielded her from herself."
Dahlia : "Hope will suffer far more than Freya. Hope's magic will be tainted by your vampire blood as well as the aggressive wolf temperament. Without the proper tutelage that only I can provide, Hope's power will grow unchecked. She will lash out at everyone, including you. She will devastate the city that you love, and then her terror will spread far beyond. I, too, am a first-born, so I was the only one to help save Freya from herself, just as I am the only one who can save your daughter! [Klaus sighs, knowing that she has a point] You've seen it, Klaus. You need me."
Dahlia : "Will you be interviewing tutors while you lie desiccated? How long, do you think, before Elijah and Rebekah release you? How old will Hope be?"
Klaus : "So, after twice failing to create a family of your own, now you wish to commandeer mine? Not going to happen, sweetheart."
Dahlia : "Family? Family only ever brought me pain. I want power. I am owed Hope's, and without it, I will slumber again within the year. Freya turned on me because I denied her a basic need-- the love of a parent. That is why I need you, Niklaus, to remain her father."
Dahlia : "Try to imagine this, you will get to raise your daughter, and I will channel the magic that has been promised to me. And, in so doing, I would help Hope to hone her craft that you couldn't possibly comprehend."
Dahlia : "With us by your side, no one would ever test you, ever again. Or, you could lie there and pray that Elijah releases you before Hope learns to call Jackson "Daddy.""
Dahlia : "I knew you were the smartest of your siblings. There's no brute Viking blood in those veins. I'm glad to see you made the right decision.""
Klaus : "I never cared for Hayley. But, you should know, the rest of my family will stand against us in defense of her."
Klaus : "You need me. I know my siblings better than anyone. Their strengths, their weaknesses. They are a powerful and determined lot! Perhaps capable of evading you for the short year you have until your slumber begins anew!"
Klaus : "You may well lose everything. But, I know how to vanquish those who stand against us, and that is exactly what I intend to do."
Dahlia : "The storm has served its purpose. Now, enough delays. I will take what is owed to me, and if the mother resists, or attempts to run, I will kill her myself.""
Klaus : "I wouldn't worry about that. What I have planned for Hayley is far worse than death."
Klaus : "Hey. Daddy's here! It's all gonna be okay, I promise."
Klaus : "And there she is. Such a beautiful child."
Dahlia : "Once we're linked, I'll no longer have to sleep a hundred years again. Your concerns for my status will ease, and I'll finally be able to focus on Hope.""
Klaus : "What do you want to do about Freya?"
Dahlia : "She served her purpose.""
Dahlia : "So, tonight, at the moon's apex, I'll end her life, and once our link is severed, the bond that I share with your daughter will become permanent.""
Klaus : "Best get on with it, then."
Dahlia : "I'm almost impressed by the lengths you'd go to for your little girl. Though, not enough to let bygones be.""
Klaus : "We are still linked, dear aunt. You may not want to punish me with that particular weapon."
Dahlia : "Hmmm. I made sure that the link between us melted along with that dagger. Meaning... I'm quite free to kill you!""
- Both Klaus and Dahlia suffered abuse at the hands of others because of their perceived weakness, and both of them subsequently strove to gain more and more power to ensure that they would never have to suffer that fate again. Dahlia accomplished this by pushing the boundaries of dark magic to increase her magical strength to unprecedented levels. Conversely, Klaus accomplished this by reveling/embracing his vampirism and striving to break his hybrid curse, which would make him the most physically powerful being in the world and allow him to create a powerful army of fellow hybrids.
- They also both have been known to massacre others who dared to defy them, and have no problem vanquishing anyone who gets in the way of their plans, or who poses a significant threat to their power or existence.
- They have both been betrayed by Esther.
- Both have negative relationships with Mikael.
- They have both created a person of their own species in some way. Klaus turned several werewolves into his hybrids while Dahlia gave some of her power to humans, essentially turning them into witches (albeit perhaps temporarily since it was originally Dahlia's power they wielded).
- Dahlia was the second to attempt to kill Klaus with the white oak stake, Alaric Saltzman being the first. However, Dahlia did so by trying to poison him with the ashes while Alaric stabbed him with it.
- Though it should be noted that right after obtaining the stake she attempted to stake Klaus with it by pulling him towards her with magic before Marcel intervened.
- Klaus is the one who stopped Dahlia. He killed his aunt by stabbing the dagger into Esther so it ran through and killed Dahlia as well.
- Klaus was the only one of Esther's children that Dahlia had respect for.
- Though this was mostly because he is the only Mikaelson sibling that wasn't fathered by Mikael along with the fact that he and Dahlia share an early life of abuse from their oppressors.