He is first mentioned in a conversation between Rose and Stefan when she warns him about the Originals. She tells him that Klaus is believed to be the most hated and feared of all the Originals and those who fear him are desperate for his approval. Over the centuries, Klaus has become a recluse who confides in and trusts only the few members of his inner circle.
For over a thousand years, Klaus had been trying to break a curse placed on him. He created the myth of the sun and moon curse in order to find the moonstone and the Petrova Doppelgänger, both of which were needed to break the actual curse. His goal was to liberate his werewolf side so he could sire his own super race of vampire-werewolf hybrids.
In 1492, he finally got his chance to break his curse when he met Katerina Petrova, the final piece necessary to break the curse. However, Katerina managed to foil his plan to use her in the sacrifice by turning into a vampire. For the next 500 years, Klaus searched for a way to break the curse without the doppelgänger, forcing generations of witches and warlocks to help him. During his search for a way to break the curse, Klaus hunted down his family and neutralized them. He also hunted Katerina Petrova, who had escaped him and stolen his moonstone.
Klaus was born to Esther and an unknown man, in a small village that would eventually become known as Mystic Falls. Klaus has six half-siblings and a step-father named Mikael, a wealthy landowner who moved with his wife Esther to the New World after their home village was devastated by a plague. Klaus was close to his family with the exception of Mikael, who was inordinately hard on Klaus.
Many years before, his mother had had an affair with a man from the neighboring village, whose inhabitants were known to be werewolves.
When Klaus' brother Henrik was killed by a werewolf, Esther performed a spell (called The Immortality Spell) which transformed Klaus, his siblings and his step-father into vampires. When Klaus made his first human kill, his werewolf gene was activated, thus revealing Esther's infidelity. Mikael then hunted down and killed Klaus' father and his entire family, not realizing that doing so would ignite a war between vampires and werewolves that has been perpetuated across the ages. Soon after turning her children into vampires, Esther placed a curse on Klaus which forced his werewolf side to lie dormant, and then rejected and abandoned him. In retaliation, Klaus murdered his mother, and framed Mikael for the act.
Klaus was with Elijah and Rebekah in 1114 AD Italy when they met a man named Alexander, a vampire hunter who was part of The Five. They spent a lot of time with him -- the brothers in order to discover his plans for killing vampires, and Rebekah because she loved him. Alexander did not seem to suspect them; they wore their daylight rings, allowing them to walk in the sun without burning, unlike the vampires whom Alexander killed on public display. However, when Klaus and his siblings were invited to a party at Alexander's home, the members of The Five daggered them in their sleep. Klaus, with half werewolf lineage, could not be neutralized by the white oak ash dagger and upon awakening killed all of The Five, including Alexander. He undaggered his siblings (except for Finn) and found out from Rebekah that the weapon Alexander had told her about was a "cure" for vampirism. As a result of slaying The Five, Klaus was forced to endure 52 years, 4 months and 9 days of the Hunter's Curse - torturous hallucinations that haunted his dreams and every waking moment in an attempt to make him kill himself, but inable to given his near-indestructible state. It was the only days where Klaus could feel the passage of time.
Klaus was an English nobleman during the late 15th century when he met Katerina Petrova, the doppelgänger whose appearance he had been awaiting for five hundred years. Planning to use her in the ritual, he had kept her entertained until the full moon, but she learned of his plan before it could take place and she escaped, taking the moonstone with her. As she fled, she encounter a vampire named Rose, whom she tricked into turning her into a vampire, thus ruining forever Klaus' plan to use her to break the curse. After Katerina turned into a vampire, Klaus assumed that her family line ended with her and that his chance to break his curse was gone forever. In retaliation, Klaus traveled to Bulgaria and murdered Katerina's entire family for her defiance.
During the 1920s, Klaus and his sister Rebekah were on the run from Mikael, who they had been running from for a 1000 years. The siblings were in Chicago in 1922 where they met the vampire Stefan Salvatore, whom Rebekah fell in love with. At first Klaus hated Stefan, but he grew to like him once he discovered that Stefan was a Ripper and they became good friends. One night, the speakeasy they were at was attacked, apparently by the police, though it turned out the raid was led by Mikael. Before he left, Klaus compelled Stefan to forget him and Rebekah. Later, when he and Rebekah were about to leave Chicago, Rebekah told Klaus that she was tired of running and wanted to be with Stefan. Klaus then forced her to choose between him and Stefan; she chose Stefan. This made him so angry that he neutralized his sister with a white oak ash dagger, then took her body with him in a car and left Chicago.
While he was still a untriggered werewolf, Klaus had a complicated life, he was close with his brothers Elijah and Henrik, and his sister Rebekah, whom he affectionately called Beka. However, he had a strained relationship with his father, Mikael, who was harder on him than on any of his siblings. Klaus even admitted to Rebekah that Mikael frightened him which made him constantly seek his approval without ever finding it. His mother, Esther, often tried to calm Mikael when he became angry with Klaus but she never tried to stop him from humiliating her son. This led him to resent both his parents and possibly to be jealous of his siblings for having their approval.
Klaus is described as being sadistic, careless, paranoid, impulsive, emotional, short tempered, volatile, manipulative, jealous, obsessive and competitive. Klaus has little to no regard for human life in general, the opposite of his half-brother, Elijah, who lives by a moral compass, has compassion and regard for human life and shows ability to feel guilt and remorse for his actions. Despite his negative traits, he has shown to be very protective of his half sister, Rebekah, who stayed by his side for centuries. Unbeknownst to any, Klaus was not the son of Mikael, but of a werewolf in another village which made Klaus both aggressive and angry. When they became vampires, all these emotions were heightened and Klaus' temper became worse than ever. Years of humiliation at Mikael's hands and Esther's indifference, coupled with her rejection of him as her son, led Klaus to kill his own mother in revenge. After this, Klaus shut off his humanity to any but his family, killing any who crossed his path. Vengeful and power-hungry, he will stop at nothing to achieve his ends and remove those who stand in his way. However, Klaus does not believe that death is a punishment as seen when he denies Katherine death, instead keeping her alive so that she will suffer for having betrayed him. He will also place usefulness before pleasure and keeps people alive when it suits his needs. He has also shown a penchant for working with witches which was mentioned by Katherine in Know Thy Enemy. Klaus also has a sense of honor and will not go back on his word although, like his half-brother Elijah, he will always look for loopholes in the deals he makes. He has also shown a sadistic side notably when he deals with humans or vampires who have crossed him, such as Elena, Damon and Katherine. However, Klaus' hunger for power actually hides a deep fear of being alone which must stem from his step-father's treatment of him. He wants the hybrids so that he will not be the sole member of his race as Esther intended when she placed the curse on him. He also desires, beyond anything else, to be reunited with friends and family as shown by his desire to have Stefan, his one-time friend, and his family back at his side. He has shown to have a softer side when he is around Caroline, but rarely shows it around other people, Caroline brings out Klaus' humanity, he also holds grudges against the people who try to kill him, or members of his family, and rarely lets it go, when ever Klaus is in a situation, where he could be killed permanently, he always reveal information that keeps him from being killed, like when he told Elijah that he didn't bury their family at sea, or when he told Stefan and Damon he is the one who sired their bloodline, Klaus rarely gets made a fool out of, also doesn't like to be made a fool out of either. He is rarely caught off guard, or by surprise, and is always two steps, ahead of his enemies, Klaus is not as forgiving as his half-brother Elijah, he rarely forgives anyone,
Klaus is an attractive figure. His height is 5'11. Klaus possesses curled light-brown hair and light blue eyes that contrasts with his pearl-white skin. As a vampire and a warrior (10th century), he is well-built. Klaus possesses a delicate and yet masculine face, possibly due to the fact that he was once a nobleman in the 15th century.
Klaus clothing style is quite casual, usually seen wearing shirts, jeans and jackets, although he can also use a more classic and refined outfit if the situation requires it (ex.: the ritual of the moonstone; the Original ball thrown by Esther). He uses accessories, such as leather bracelets or necklace as seen in some scenes at the beginning of season 3.
Klaus and Caroline's relationship has slowly been coming together ever since he saved her life on her birthday in Our Town. Klaus later develops an unrequited romantic interest in Caroline, and invites her to his family's ball. At the ball, they dance and talk together and she soon discovers a soft side to Klaus. When she returns home that night, she finds a hand-drawn picture of her and a horse, from Klaus. As the series progresses, Klaus falls for her even more because she's too smart to be seduced by him, she's beautiful, strong, and full of light. If one thing is for certain about the two of them, it’s that there is definitely something there. Whether it’s just flirtatious chemistry or something more but they definitely have a spark. After Klaus leavesMystic Falls, he tells Caroline that intends to be her last love, no matter how long it takes. He believes one day that she will one day choose him and let him show her the world.
Rebekah is Klaus' younger half-sister. Out of all his siblings, he is most close to her and very protective of her. Klaus cares very deeply for Rebekah, he seems to have a lot difficulty showing her that it is true. They are loyal to each other. They have never left each other's side and stood by one another no matter what happens. But after Klaus was "supposedly" killed by Alaric in The Departed, Rebekah is heartbroken after losing her older half-brother whom she loved and never left her. When she finds out in the season four premiere that he was still alive, their relationship started to completely and totally fall apart when he chose to save Caroline over his own sister. Rebekah confronted him about how she never stopped loving him through everything. It was always her that was there for him when Finn, Kol, and Elijah weren't. She now realizes he truly doesn't love her when he tells her they are no longer family. But later in the season, Klaus saves her when Kol nearly kills her with a white oak stake. Even when she hates him, he shows that he still cares and loves her regardless of what's happened between them.
Super Strength - Being A Original/Werewolf Hybrid, Klaus is much stronger than any normal vampires, werewolves, hybrids, and humans. He is able to decapitate other species with a single swipe of his arm and shatter windows and doors with small objects. Like regular vampires he grows stronger with time, his muscular physique is much more defined and his muscle mass is enhanced.
Super Speed - Being A Original/Werewolf Hybrid, Klaus is much faster than any normal vampires, werewolves, hybrids, and humans. He is able to stop other supernatural species in their tracks and run miles in mere minutes. His speed also grows faster with time.
Heightened Senses - Being A Original/Werewolf Hybrid, Klaus has far more enhanced, keen senses of hearing, sight, smell, and taste than any original vampires, normal vampires, werewolves, hybrids, and humans. His senses improve over time.
Super Agility - Being A Original/Werewolf Hybrid, Klaus possess much more superhuman stamina, flexibility, reflexes, agility, and dexterity, than any original vampires, normal vampires, werewolves, hybrids, and humans. He can move, jump, climb, and run incredibly fast without difficulty or exhaustion.
Enhanced Healing Factor - Being A Original/Werewolf Hybrid, Klaus can recover/heal/regenerate from any injury much quicker and more effectively than any original vampires, normal vampires, werewolves, hybrids and humans.
Super Durability - Being A Original/Werewolf Hybrid, Klaus can take far more trauma than any original vampires, normal vampires, werewolves, hybrids, and humans, can without much discomfort or injury. Vervain and wood do not weaken him. A Original/Werewolf Hybrid is practically indestructible.
Mind Compulsion - Being A Original/Werewolf Hybrid, Klaus can compel the minds of most sentient creatures: humans, vampires, and hybrids. It has not been proven that Klaus can compel werewolves, and he cannot compel a supernatural hunter.
Immortality - Being A Original/Werewolf Hybrid, Klaus does not physically age. He is immune to all forms of illnesses, toxins or poisons. He does not need to eat, drink, or breath. He has eternal youthful beauty with perfect features, flawless smooth skin. He also possess an almost eidetic memory, and cunning intelligence.
Dream Manipulation - Being A Original/Werewolf Hybrid, Klaus can control dreams and subconscious. He can produce and modify dreams, bestow nightmares or lucid dreaming. Other effects of this ability is the distortion of reality and being able to trap someone in their dreams.
Emotional Control - Being A Original/Werewolf Hybrid, Klaus has a limited degree of control over his own emotions. He can switch off his humanity to make killing easier for him.
Day Walking - Klaus is able to move around during the day.
Hybrid Sire Bond - Hybrids are all turned by Klaus from werewolves. In doing this he has taken their pain of turning into a werewolf away. They, thus, feel obligated to serve Klaus because his blood created them and have limited free will, along with lack of control. They listen to Klaus as if they're his slaves.
Healing Blood - Only Klaus’ blood is capable of healing a vampire from the bites of a hybrid or werewolf.
Transformation Control - Klaus has complete control of his transformation since he first transitioned from original vampire to werewolf to original hybrid when he broke the curse. Elijah informs Klaus that he remained a wolf for 2 days, even when the sun was up. As seen with Klaus when he bit Katherine, a hybrid can transform partially, displaying their wolf eyes and teeth. It can be assumed that unlike non original hybrids, Klaus has complete control and awareness of his actions, even in his wolf form.
Werewolf Bite - Werewolf bites contain a poison which is fatal to vampires. As the Original Hybrid, Klaus' bites take effect quicker than a normal werewolf/hybrid bite.
Lycanthrope Enhancement - Hybrids can use their wolf traits to further enhance their abilities;
Hybrid Claws - Hybrids can grow claws from their nails, even well they are still in their human form, it is unknown how sharp a hybrid claws are, well klaus was still in tyler's body, it was shows that a hybrid's claws is sharp enough, to penetrate a hybrid's very durable skin, and is able to rip another hybrid's heart out.
Immunity to Silver - While hybrids can be hurt by silver physically, they appear to immediately heal from the wounds caused by it. Magic bonded to silver cannot affect hybrids due to their werewolf heritage.
White Oak Stake - The only physical weapon that can permanently kill Klaus, It comes from an Ancient White Oak tree during the time of the genesis of The Originals. It was at first thought that the stake used to kill Mikael was the last white oak wood in existence, but it was soon discovered by Rebekah and Niklaus that there was a apling of the original tree to replace the old. This tree was eventually cut down and later turned into stakes, one of which was used to kill Finn. Some of these stakes were destroyed but Esther used Alaric's ring to make the last one indestructible. This stake almost killed Klaus and later killed his brother, Kol.
Uninvited Invitation - In order to enter any house owned by humans, they had to be invited by that person. Once invited the vampire cannot be uninvited. If a vampire lives in a house, other vampires can enter freely and if vampire is in the house without being invited in it will become disoriented and will begin to suffocate.
Magic - As a supernatural entity Klaus can be harmed or killed by a witch/warlock that can channel enough power. Considering his level of power however this would likely be very difficult to achieve. Klaus however mentions in Bringing Out The Dead that Esther can kill him. Her knowledge of the spell that created vampires and thus ability to reverse it could be the deciding factor in this.
Desiccation - Like any vampire lack of blood will immobilize Klaus. This process can be artificially induced by a witch through the use of a dark magic spell which stops a human's heart and having other people make and hold a blood connection to Klaus.
Hunter's Curse - If a vampire kills a member of The Brotherhood of the Five then they will be tormented by the hunter until they kill themselves or if the hunter is replaced then they will be free of torment.
Events Influenced By Klaus' goal of breaking the Curse
Katherine turning into a vampire to avoid being sacrificed. (Katerina)
Isobel's return to Mystic falls (under compulsion of Klaus) and with the help of Maddox, They retrieve the moonstone, Katherine, and Alaric. After Isobel's job was finished she was compelled by Klaus to take off her necklace and burn to death in the sunlight. (The House Guest, Know Thy Enemy)
Gloria - She was a powerful, 116 year old witch, and also the owner of a Gloria's. Unlike vampires, Gloria is not immortal. Despite her charmingly good looks, and forty-year old appearance, Gloria is the only witch ever known to discover a spell that could decrease the speed of human age. She was killed by Katherine.
Greta Martin - She was a witch. Jonas' daughter and Luka's sister. She is first mentioned in The House Guest by Luka. She is kept by Klaus and that is the reason Jonas and Luka join Elijah in his quest to retrieve the Moonstone but she is present with Maddox in the Alaric´s house and she says she is happy to see Klaus (Alaric´s body). In the episode The Last Day, Greta mentioned she was never "lost" (abducted), it makes clear that her intentions were always to help Klaus. She was killed by Damon.
Maddox - He was a warlock and was working with Klaus, aiding him with his magic. He is first seen in Know Thy Enemy. He was killed in The Last Day by Damon and Matt.
Hybrids - Hybrids are loyal to Klaus and will seek his acceptance because his blood created them.
Isobel Flemming - She was a vampire. Isobel was an expert researcher and Elena's mother. She manages to contact Klaus but when she finds him, Klaus compels her to gather information about Mystic Falls (Katherine, Elena, Stefan, Damon, Bonnie, etc.). He then compels her to commit suicide by exposing herself to the sunlight when her job was done.
Stefan Salvatore- After Damon was bitten by a werewolf, Stefan seeks Klaus to find a cure. During the meeting Stefan with Klaus, Klaus reveals the cure is the Klaus´s blood but Klaus manipulates Stefan to serve or else he would not give the cure. Klaus forces Stefan to drink countless bags of human blood as he wanted to awaken Stefan's ripper side. In the end, despite the attempts he had made in the second season to control his blood lust, Stefan gave in to the blood and killed a young girl at Klaus' order. A pleased Klaus then told Stefan that they would be leaving town that night.
Mikael - Mikael was searching for Klaus and Rebekah in Gloria's and asked Stefan if he knew either of them and where they might be, but under Klaus' compulsion, he says he has never seen them in his life.
Trevor - He was a vampire and a very close friend of Rose. He was killed by Elijah for betraying him by helping Katherine escape from Klaus during the 15th century.
Rose-Marie - She was a vampire and a very close friend of Trevor, she and Trevor tried to stay hidden from Klaus in the 15th century and have both been running from him ever since. Rose unintentionally helped to turn Katherine into a vampire. She then helped both Damon and Stefan to help protect Elena from Klaus and from being in danger. Rose was staked by Damon to keep her from suffering from a werewolf bite.
Elena Gilbert- Elena decided to surrender to Klaus to prevent any of her loved ones from suffering. During the sacrifice, she agreed to help Klaus to break the curse, with the hope that Elijah and Bonnie could destroy him but in the end, Elijah betrayed Elena and the others and he escaped with Klaus.
Damon Salvatore - Damon wanted to protect Elena and Stefan from Klaus, causing him to work with Mason Lockwood and Katerina Petrova to destroy the Originals, once and for all.
Katerina Petrova - Klaus had her under his control, for the purpose of destroying the curse. Klaus finds Katerina in England after being exiled from Bulgaria. Katerina says that Klaus was kind, gentle and caring with her but then she learns that she will be used in a sacrifice and escapes with the moonstone.
Witches - Most witches despise Klaus, possibly due to him being a Vampire. Klaus' mother has even broken the door to the other side to foil his plans. He has, however, had a few allies and friends that were witches.
Silas - Silas made Klaus think that he stabbed him in the back with the indestructible white oak stake and threatened Klaus to get the Cure for him.
In the books, Klaus is of unknown age, but is at least from the Bronze Age. He seems to have fought in every major war through time, most notably in Alexander the Great's army, in the Trojan War, and in the wars that led to the Roman Empire's downfall (on the Germanic side). He then decided to stick around the general area of Germany where, sometime in the 15th century. In the books, Klaus was the one who transformed Katherine into a vampire, in the TV series, it ended up being Rose who played the part, and Klaus and Katherine's back stories have been completely changed from the books. Klaus shows great strength and durability at all times of injury and other vampires feared law. For example: Klaus manipulates the mind of Katherine to inform the brothers Salvatore's that he is dead (Katherine kills Klaus centuries ago, because he is no longer useful). Klaus continually avoids Elena messages or visions to Bonnie and Stefan. A vampire must be invited by someone to enter your home, but Klaus enters Vicki's house and violently murdered her without one. Stefan and Damon fight against Klaus, but do not do any harm. In the books, when everyone tries to fight against Klaus, all of the weapons used against him fail. Klaus more or less kills Stefan, and nearly kills Damon as well, until an intervention from Elena's spirit, leading an army's worth of unquiet Civil War ghosts against him. The ghosts carry a screaming Klaus away, and his current whereabouts (and state of being) are unknown. It was later revealed that when he had attacked Meredith's grandfather before the books started, he had in fact been trying to capture Meredith and her twin brother Cristian. He failed to capture Meredith who became half-human, half-vampire as a result, but got Cristian who became a vampire himself.
German variation of "Nicholas ". From the Greek Νικολαος (Nikolaos) meaning victory of the people. It's the name of a saint who is at the origin of Saint Claus legend.
CLICK SHOW TO SEE TRIVIA (WARNING: THERE WILL BE SPOILERS)
In the novels, the character of Klaus was partially based on Rutger Hauer's character (John Ryder) in the 1986 movie The Hitcher.
John Ryder "The Hitcher": It is not clear where he came from, who he is or what his motivation is, but the one thing that is known is that his name is John Ryder. He has a sadistic drive for killing everyone and anyone he comes across. From what it seems, he is suicidal and he's on the look out for someone to do the task for him.
Given how far back his machinations have stretched, Klaus is more-or-less the main antagonist of the series overall, although he does not appear until the final third of season 2.
Klaus is the only main antagonist to be in the main cast, and consequentially the only one appear in the most episodes during one season (18). John Gilbert appeared in only the final 5 episodes during Season 1, Klaus himself only appeared formally in the last 4 of season 2, Esther only appeared in 3x08, 3x13, 3x14, 3x15, 3x19, and 3x20, and Silas has appeared in 5 episodes so far.
Klaus is the Original with the most appearances so far (37).
In the novels, Klaus seems to have fought in every major war through time (Alexander the Great's army, in the Trojan War, and in the wars that led to the Roman Empire's downfall).
In the series, Katherine meets Klaus in England but in the books, Klaus remains in Germany for centuries where Katherine is turned into a vampire.
Klaus seriously affects the life of Katherine in the books and the series. In the books, Klaus controls the mind of Katherine and makes insane, cruel, sadistic, cold, unstable, murders, etc. In the series, Katherine was not transformed by Klaus and was never his student but she is damaged by the abandonment of her daughter, the death of her entire family and the terror of The Originals.
Klaus was said to be the oldest vampire in the history of time in season 2, but it was revealed that Mikael was actually the oldest vampire.
Klaus was revealed to not actually be a full vampire, but instead a half-vampire, half-werewolf hybrid.
Klaus takes the Originals resting place everywhere he goes, but keeps them well hidden at the same time.
In the books, Klaus is weak against the Spirits (Ghosts), because he can´t attack them. In the series, he is also somewhat weak against spirits since it's the power of the dead witches that Bonnie was using to destroy him.
In the books, Klaus was the one who killed Vicki where as, in the series Vicki was turned into a vampire by Damon and then staked by Stefan.
He and Stefan are the only characters to have permanently killed another main character (Jenna and Vicki respectably).
In the novels, it was never established if Klaus needed a ring to walk in the day.
In the novels, Klaus has his first and last battle against Elena, Stefan, Damon, Bonnie, Meredith, Matt and Caroline on the 31st of October. After that, the whereabouts of Klaus and his condition remains a mystery.
Klaus, Isobel, Rose and Katerina are the only characters thus far to have an episode named after them with Klaus being the fourth and first male.
Klaus was introduced to Katherine Pierce on his birthday.
In the novels, Klaus is an Old One and the oldest of all vampires but in the series, Niklaus is a Original/Hybrid and the oldest living Werewolf.
In the series, Niklaus shares similarities with Markus Corvinus of the Underworld film series.
Niklaus manages to break the curse using four women of different species: Greta (witch), Jenna (vampire), Jules (werewolf) and Elena (Doppelgänger).
In the series, he corrupted Stefan like he corrupted Katherine in the books.
Klaus is the first recurring role to be updated to series regular during their sophomore season Season 3.
Klaus, besides Damon Salvatore, has killed the most characters in the series but most of Klaus' kills were off-screen.
Klaus is the only hybrid shown to drink any blood on-screen.
Klaus made the insinuation that Elena, Jenna and Jules are goddesses (Maiden, Mother and Crone) for the sacrifice.
In 1492, Klaus had all the elements to break the curse of the sun and the moon, but Katherine manages to escape with the Moonstone.
In the books, Klaus was never human, but a pure blooded vampire, and was very very old in age. In the show he was once a potential warlock and far younger in age than the books.
Rebekah assumes that Klaus' reasoning for making hybrids is due to his fear of being alone.
In Homecoming, Klaus says "I will kill you and every one, you've ever met" to Stefan, this is how Katherine describes him when he's betrayed or angry. She tells this to Elena and Stefan in Katerina and Damon in The Last Day.
Klaus is a Beatles fan as he said in The Last Dance, claiming that they made the 60s bearable.
Of all the Originals, Klaus can be considered the most vindictive and spiteful.
He was originally supposed to be killed at the end of the third season but Julie Plec decided not to after she saw him acting.
Klaus is the first Original to become a regular.
It appears that Klaus daggers his siblings when they decide to abandon him. He daggered Rebekah for wanting to leave with Stefan . As Kol is a loose cannon he probably wanted to explore the world for himself and was tired of dealing with Klaus so Klaus hunted him down and daggered him too. The only sibling he didn't dagger was Finn, who was daggered by hunters, though Klaus decided not to remove the dagger.
Klaus seems to be a very talented artist. He even has a landscape painting hanging in the Hermitage museum and sometimes gives his paintings away to others for fun. His favorite thing to draw is Caroline.
Along with Elena', all Klaus' chances to make more hybrids died. Also, because Elena might ended Petrova bloodline.
Klaus has been portrayed by three actors, the most than any other character in the series:
He is the only one shown to be protective of Rebekah.
Despite the fact that most people call Katherine with the American version (Katherine) of her name both Klaus and Elijah both call her by her original name Katerina.
It is revealed in episode 4x01, Growing Pains, that Klaus' body only survived the White Oak Stake because Alaric closed the coffin immediately after staking Klaus. In order for a fire to burn correctly, it needs access to oxygen. This is explained shortly by Klaus himself (Michael Trevino) "...When I assumed I'd be a pile of ash, but apparently fate and oxygen intervened..."
Caroline brings out Klaus humanity and his playful side. He thinks that Caroline is beautiful, strong and full of light.
Klaus is the only Original to kill another Original, Mikael.
Klaus, Finn, and Kol are the only Originals with a known bloodline.
So far Klaus has the largest known bloodline than any other Original.
The Casanova - Katerina (a little) and, most recently, Caroline
All Love is Unrequited - Caroline. Despite his attempts to woo her, and the fact that she knows he's in love with her, she is in love with Tyler and keeps refusing his advances. Still has chance to be averted, though is increasingly unlikely given the time he has left in Mystic Falls. See also Sympathy for the Devil .
And I Must Scream - Shared with family. However, instead of being daggered, Klaus must literally be chained and dessicated. When Alaric was turned into a vampire/vampire hunter, Klaus could do nothing to prevent Alaric from staking his dessicated body with the white oak stake .
(To Katherine in 1492) "Niklaus is the name my father gave me....Please, call me Klaus." -- Klaus
(To Elijah in 1492) "Love is a vampire's greatest weakness, and we are not weak, Elijah. We do not feel, and we do not care." -- Klaus
(To Katherine) "How could you? You betrayed me and fled England before I could even give you the details. But.. I did find your birthplace and I slaughtered your family. So I guess we`re cool." -- Klaus
(To Katherine) "Let`s just hope that Elena isn't as stupid as you were." -- Klaus
(To Damon) "I thought I remind you and your brother not to do anything you regret." -- The Last Day
(To Damon) "Let me be clear. I have my vampire, I have my werewolf. I have everything I need. The ritual will happen tonight. So if you want to live to see tomorrow, don't screw it up." -- The Last Day
(To Damon) "I thought I remind you and your brother not to do anything you regret." -- The Last Day
(To Elena) "You got me all nervous. I thought you had done something stupid." -- The Last Day
(To Damon) "I`ve heard about you. The crazy, impulsive vampire in love with his brother`s girl. I knew one of you would try to stop me. It was just a 50-50 guess on who." -- The Last Day
(To Stefan) "I heard about this one vampire, crazy bloke, always on and off the wagon for decades. When he was off, he was magnificent. 1917, he went into Monterrey and wiped out an entire migrant village. A true ripper. Sound familiar?" -- As I Lay Dying
(To Stefan) "There it is. You want to save your brother? How 'bout a decade long bender? And I have big plans for you when we leave this town." -- As I Lay Dying
(To Stefan): "I`m not mad, just curious. Rebekah seems to think you`re holding on to something. A piece of your old life. The thing is, she`s got flawless instincts, borderline supernatural. So I thought, I would check it out. See for myself what it is you`ve been hiding. Welcome back to Mystic Falls, Stefan."" -- Disturbing Behavior
(To Bonnie) "You put a rather large kink in my plans, sweetheart. The whole point of breaking the curse and becoming a hybrid was to make more hybrids. I haven`t been able to do that. Now my bet is, it has something to do with the fact that you`re still breathing.." -- The Reckoning
(To Bonnie) "If Bonnie`s successful, he`ll live through his transition. Go on, then. Go and fetch your grimoires and enchantments and what-not. I`ll hold on to Elena, for safe-keeping." -- The Reckoning
(To Elena) "It`s always nice to see a vampire in his true element. The species has become such a broody lot." -- The Reckoning
(To Stefan) "Now this is fascinating. I`ve never seen this before. The only thing stronger than your craving for blood is your love for this one girl." -- The Reckoning
(To Rebekah) "You know how much The Original Witch hated me. Do you honestly think I would do anything other than the opposite of what she says?" -- The Reckoning
(To Rebekah) "Yes, go tend the dinner. Leave the blades to the men, little sister."
(To Elena) "I`ll get straight to the point, love. People have been after me for a thousand year and I`m always one step ahead, so whatever it is you`re trying. Go for it, give it your best shot. You won`t succeed."
(To Tyler) "Human life is just a means to an end. Our means, to our end." -- The New Deal
(To Rebekah's dead body) "Here we are, Rebekah. Home sweet home. Only took a thousand years. And to think, I was counting on you being here with me. But that's all ruined now, isn't it? I'm so sorry, sister. We'll meet again one day." -- The New Deal
(To Caroline) "Do you really think that low of me?."
(To Caroline)"And I could let you, die, if that's what you want, if you really believe your existence has no meaning. I thought about it myself once or twice over the centuries, truth be told. But I'll let you in on a little secret, there's a whole world out there waiting for you, great cities and art and music, genuine beauty, and you can have all of it, you can have a thousand more birthdays. All you have to do is ask." -- Our Town
(To Damon)"Crazy or not. That kind of love never dies." -- Our Town
(To Esther): "Enough. All this talk is boring me. End this now, Mother, or I’ll send you back to Hell." -- All My Children
(To Bonnie): "There’s Jeremy, playing fetch with his new puppy. Oh, isn’t that just the most adorable thing you’ve ever seen?" -- The Murder of One
(To Bonnie): "Yeah, you’ll have to excuse the mess. Apparently Damon hurt her feelings. Go on, help him. Save the man who turned your mother into a vampire." -- The Murder of One
(To Stefan): "So, the fate of the entire vampire race depends on you finding a stake? And to get it we need you to pass out. Which means that I feel totally justified doing this."[breaks Alaric`s neck] ""There sleeping like a baby"" -- Heart of Darkness
(To Stefan): "That’s a little gratuitous, don’t you think, Stefan? I would have been more gentle."" -- Heart of Darkness
(To Esther) "Your trap failed Mother. I still live and I will go on living and should your beloved spirits try to preserve you again I dare you to come after me. I will build an army so big no one will ever touch me. My survival will haunt you for eternity. You will never destroy me!" --Do Not Go Gentle
(To Jeremy) "Well, for starters, young Jeremy here could show some manners and invite me inside." --Before Sunset
(To Stefan and Damon) ""Hmm..poor lad. Loses one questionable father figure only to be replaced by the likes of the two of you." --Before Sunset
(To Damon) "Oh, I know all about my mother’s invulnerable little creation and that’s why I’m here. I’m leaving town, just need to pick up a few road trip necessities. Spare tire, flashlight, Doppelgänger." --Before Sunset
(To Stefan and Damon) "Just so we are clear. The sun sets in about eight hours. If we don’t succeed before then, Elena will be dead, I’ll be gone, and the rest of you will be left to fend for yourselves." --Before Sunset
(To Stefan, Damon, and Bonnie) "Before we all walk through these doors, let’s get on the same page, shall we? I was the one who created your vampire bloodline, therefore I am responsible for your lives and Tyler’s life, Caroline’s life, and of course, Abby’s life, should anything go wrong." --Before Sunset
(To Damon) "I’m not lying. But go ahead, call my bluff, let the teacher kill me. You’ll all be dead soon thereafter." --Before Sunset
(To Elena) "You know Stefan blames me for trying to tear him from his brother, but I think we both know who really came between them. You. That’s why you won’t choose. You know once you pick a Salvatore, you’ll destroy their bond." --Before Sunset
(To Elena) "Consider this me doing you a favor. Once you’re dead, you won’t have to choose. No broken hearts. Their family stays intact. But just between us girls, who would you have picked?" --Before Sunset
(To Caroline) "Your mouth was all over me, I was an innocent victim!"
(To Rebekah) "I mean it’s pathetic really, isn’t it? How she continues to hand her heart to any man who shows her a hint of affection. You think she would have learned by now from the endless cycle of disappointment and deception."
(To Caroline) "I never answered your question; if I ever thought about being human. Once, I was on a trek in the Andes, and a hummingbird flew up to me. It just hovered there, staring at me, its tiny heart was pattering like a machine gun. And I thought, what a thing, you know, to have to work that hard every day just to stay alive. To be constantly on the verge of death and how satisfying every day must be that it survived. And that was the only time I thought about being human."
(To Stefan) ""Loneliness Stefan, that's why you and I memorialize our dead. There's the briefest of moments where we hold their life in our hands and then we rip it away and we're left with nothing. So gathering other peoples letters or writing their names on a wall is a reminder that we are left infinitely and utterly alone.""
(To Damon) "Twelve... that's a number. That's how many of my hybrids I slaughtered with my sword. Tree. That's how many days it took me to quell the urge to kill your brother, after he knowingly watched as I walked into a death trap. One that's the number of purposes you serve."
(To Jeremy) "You really think I care for an instant about my bloody hybrids. I want the cure so I could destroy it, I would have killed you all the second we dug it up. But now I'm just going to watch you burn instead.'"
(To Tyler) ""See, now I think you’re just telling me what I want to hear. I mean, you did call me pathetic earlier. And wouldn’t it be more pathetic of me to help now knowing that, hours ago, you announced your plan to kill me in a manner of which you’re still debating because you want it to have a certain amount of flair? Just asking."
(To Elijah) "I gave you that opportunity. And you sided against me. So if I run, it'll be to chase her. And as your only living brother, I will make it my cause that you never know a moment of happiness."
(To Rebekah) "You can stand idly by as poor April takes her final breath. You can ask, "Why does this always happen to innocent people? Where do the spirits go? Was there anything I could have done?" That is what it means to be human, sister. You give humanity too much credit."