Rebekah Mikaelson

Rebekah Mikaelson is a free-spirited Original Vampire. She has been a recurring character in Season Three and Season Four. Rebekah was the romantic interest of Stefan Salvatore in the 1920's, daughter of Mikael and Esther and also the only sister of an unnamed deceased brother, Elijah, Finn, Kol and Henrik. She is also the only half-sister of Niklaus. After the death of Henrik, she became the youngest sibling in the family. She used to live in Mystic Falls and had her own house. 

She now lives in New Orleans with Elijah and Klaus. She joined her brothers in the The Originals, having a lead role. Rebekah is the only daughter of Mikael and Esther, wealthy land owners from Eastern Europe in the 10th century. She is the sixth of seven siblings, Elijah, Finn, Niklaus, Kol, Henrik and an unknown older brother who died while the couple still lived in the Old World. Not much is known about Rebekah's early life, other than that she was born in the New World, where they lived in peace among werewolves for twenty years. 

Jeremy Gilbert

Jeremy Gilbert is the adoptive brother and biological cousin of Elena Gilbert and he is a medium. His best friends are Matt Donovan and Bonnie Bennett who is also his girlfriend. Since he came back to life, he's been living in the Salvatore Boarding House with his sister (when she's not at college) and her boyfriend, Damon Salvatore since their house was destroyed by her after his death.

Prior to the beginning of the series, his parents died in a tragic car accident that Elena managed to survive thanks to a vampire, Stefan Salvatore. As a way of coping with the accident, he started dealing and using drugs but soon stopped after the death of his first girlfriend, Vicki Donovan, supposedly because of an overdose. He overdosed on pills after drinking vampire blood in the hope of becoming a vampire and being able to turn off his emotions. He did this following the death of his second girlfriend, Anna. However his attempt to become a vampire failed and the blood healed the damage the pills did.  

He started a romantic relationship with Bonnie Bennett which ended after he kissed Anna. Jeremy was shot by Sheriff Forbes after Damon dodged the bullet and was revived by Bonnie, who is a witch and has connections to dead witches with the power to bring him back. However the spell that caused him to be revived gave him the power to see ghosts and he was haunted by Vicki and Anna. He later went to live with family friends in Denver, after being compelled by Klaus to stand in front of a speeding car. Elena feared for his safety and got Damon to compel him to leave. He returned to Mystic Falls after Elena and Damon went to get him once Klaus found out where he was. He was turned into a vampire hunter and became a member of The Five. After helping Shane free Silas, he was forced by Katherine Pierce to raise the immortal, who then drained him of his blood and snapped his neck. He was able to survive numerous deaths due to the Gilbert Ring, but since he turned into a supernatural being, this death would last. His body was burned inside the Gilbert House because Elena could no longer keep the house after losing the only family she had left. So she decided to burn the house down to make it a good cover story for Jeremy's death. 

Tyler Lockwood

Tyler Lockwood is a main character and hybrid who played for the football team at Mystic Falls High School. He was a werewolf until becoming the first successful hybrid after Klaus.

He is the son of Richard Lockwood and Carol Lockwood, and the nephew of Mason Lockwood who was a werewolf. He was initially portrayed to be arrogant, selfish and a bully. But after triggering the family curse that turned him into a werewolf, he has learned to tone his behavior down. Before this revelation, he was referred to many times as a "dick," by both his best friend; Matt Donovan and Jeremy Gilbert. He is shown to have an athletic build, and great strength as a human. He also has a short temper and becomes angry very easily. He didn't understand why he behaved the way he did, until Mason came to visit after Richard Lockwood's death.

Initially after becoming a hybrid, he was grateful to Klaus for taking away his pain at turning every month however soon becomes angered at the prospect of being sired to him. He manages to break the sire bond and continued to help other hybrids break the curse of being sired. However this came at a price as once Klaus found out his actions, murdered his mother and last remaining family member. Since then, he swore revenge on Klaus for his actions.

Caroline Forbes

"He is your first. I intend to be your last however long it takes." - Klaus to Caroline.

At the beginning of Season 3, Caroline and Tyler started a romantic relationship. It was then affected when Tyler was turned into a Hybrid by Klaus, which created a sire bond that Caroline didn't approve of.

Klaus tells Tyler that he wants him to bite Caroline, he flatly refused but then Tyler accidentally bites Caroline.

Tyler went to Klaus for help and he agreed to save her. Klaus went to Caroline's house to save her and after they had a conversation, he fed her his blood.

Tyler is forced to make a decision on whether he wants his freedom at the cost of having to go through extreme pain to break his sire bond to Klaus. He leaves Mystic Falls, after hurting Caroline caused by his sire.

In Dangerous Liaisons, Klaus then invites Caroline to the ball, and continues to persuade her although she does not reciprocate those feelings, claiming she is spoken for by Tyler. Caroline speaks with Klaus and she tells him that let to Tyler free. They discuss and Caroline ends up leaving the house of Klaus. When she arrives home, she finds a drawing Klaus sketched for her where he thanks her for her honesty.

Later, Klaus expressed a romantic interest in Caroline, who, despite his charm, turned him down several times.

Elijah Mikaelson

Elijah was first introduced when two vampires named Rose and Trevor called a person on Elijah's inner circle in the hope that he would come to meet them and pardon them because they were tired of constantly running from the Originals. They held Elena captive in the hope of using her as a bargaining chip. Initially skeptical of their claim of having the Petrova doppelgänger, by testing whether Elena was human, he proceeded to smell her neck. Surprised, he confirmed that Elena was indeed a human and alive. He forgave Rose because she helped Trevor out of loyalty to him which he respected, but he executed Trevor by decapitation for his betrayal of having helped the second Petrova doppelgänger, Katerina Petrova, escape.

As they were leaving the house that Rose and Trevor were hiding out in, the Salvatore brothers came to rescue Elena. They shot Elijah in the hand with a wooden stake, Elena then came out and threw a vervain grenade which exploded and burnt his face; however, he soon healed. Stefan shot multiple stakes at him and eventually tackled him to floor. When Elijah got the upper hand and was about to kill Stefan, Damon then staked him with a broken coat rack, pinning him to the wall; however, some time later, he came to back to life and pulled the stake out of him.

Elijah saves Elena and Damon from Klaus' minions.When Rose and Damon went to see a vampire named Slater looking for information about the curse, Elijah appeared and gave a guy a 100 dollar bill in exchange for some coins. He listened to the conversation for a while before throwing some coins at the web-Café's special UV protected glass. It shattered, which sent the vampires inside running for cover. Later that night, he compelled Slater to call Rose (who was with Damon) and tell her that they can stop the sacrifice by dispelling the moonstone. Elijah then further compelled Slater to stake himself.

Mikael

"Nobody cares about you anymore, boy. What do you have? Other than those whose loyalty you forced. No one. No one." -Mikael to Klaus in Homecoming episode.

Mikael was an Original Vampire who was once a wealthy landowner in a village in Eastern Europe. He is the patriarch of the Mikaelson family. He was the father of Elijah, Finn, Kol, Rebekah and Henrik and the step-father of Niklaus. He was in his late 40's to early 50's, and was seen to be strong, controlling, domineering, strict, and authoritarian in nature. After moving to the New World, his wife bore six children and his family was quite close, though he and Klaus didn't get along well at all, due to the fact that Klaus was not his son and was from a Werewolf Bloodline. His wife had been unfaithful many years before and when he found out about her affair, he hunted down and killed Klaus's father and his entire family, not realizing that he was igniting a war between species that rages to this day, the war between the vampires and the werewolves. Mikael was the one who asked Esther (wife) to turn the family into vampires. 

In Homecoming, Mikael helped Elena and the Salvatore Brothers to lure Klaus to him so he could kill him for good. To do this, Klaus needed to think that Mikael was dead, so Elena temporarily daggered him and later revived him. When Mikael returned to life, Rebekah was there to talk with him. He said that his intent was never to kill her, only Klaus as revenge for killing her mother. Rebekah told him that she knew what Klaus had done, but blamed Mikael for making Klaus this way, saying that it was not Klaus who destroyed their family, but Mikael when he turned them into vampires. 

Mikael meets with Klaus for the first time in 1000 years. Later, Mikael showed Damon the White Oak Stake, the only weapon that could permanently kill an Original. Damon asked him why he feeds on vampires. His reply was:"I had a hand in creating vampires but the blood lust was never my intention. Over the centuries, I've learned to feed from the predator, not the innocent."

Mikael kills Elena in front of Klaus. When Stefan came in, he fed on him and went with Damon to the Lockwood Mansion to proceed with the plan. At the mansion, Mikael found himself surrounded by hybrids. Klaus says that his hybrids will kill Mikael. Mikael replied that they cannot kill him, to which Klaus says "But it will make a hell of a party game". When Klaus came to the door, he tried to get Klaus to come out of the house to fight him, to no avail. Mikael dies.
Mikael bursting into flames after getting staked with the White Oak Stake. 

Damon Salvatore

 “Let me be clear about something. If it comes down to you and the witch again, I will gladly let Bonnie die. I will always choose you." - Damon to Elena.

Damon Salvatore is Stefan's elder brother. He was born in 1840 and lived in the colonial town of Mystic Falls with his brother Stefan and his father, Giuseppe Salvatore. He became a vampire in 1864. At the time of his return to Mystic Falls, Damon and Stefan hadn't seen each other in fifteen years due to their bitter, violent relationship. 

Damon is some sort of a bad guy. He looks bad, he's acting bad and make people getting pissed off of him but deep down in his heart, he's a very emotional guy and has a great sense of sympathy towards his dear one. He will do anything to save them. He's even more emotional than his brother Stefan and willing to fight and sacrifice himself for the sake of his love. Later, after Katherine, Damon and his brother Stefan both fall in love with Katherine's doppelganger, Elena Gilbert. 

Damon's sole purpose in coming back to Mystic Falls was to free Katherine Pierce, the vampire who turned him and the woman he deeply loved. After realizing that Katherine never loved him, his love for her fades as his friendship with Elena, Katherine's descendant and doppelganger, grows. Due to her impact on him and the strengthening relationship with his brother, they begin working together and protect Elena, her friends and family. He currently lives with his brother, ex-girlfriend Elena (when she isn't away at college), and her brother Jeremy Gilbert in the Salvatore Boarding House.