Kol Mikaelson is one of the Original Vampires, born in the 10th century to Mikael and Esther. Kol is the fourth son, the younger brother of an unnamed deceased brother, Elijah Mikaelson and Finn, the older brother to Rebekah and Henrik, and the half-brother of Niklaus.
Kol is a member of the Mikaelson Family.
Throughout his life, Kol struggled emotionally with his status as the black sheep of the family, and the belief that his siblings considered him to be more of a nuisance than their own brother. He was shown to be rather spiteful and jealous over Marcel Gerard, whom he perceived was treated more like family than he ever was. As a result of this insecurity, Kol often lashed out violently which earned him a dangerous reputation and on occasion, the ire of his siblings. In reality, his bad behavior is revealed to be simple cries for attention.
During the fourth season of The Vampire Diaries, Kol feared the return of Silas and was adamant about stopping him. He antagonized the Mystic Falls Gang and at one point Elena Gilbert proposed a truce between them. However, the truce was really a setup to kill Kol and it ultimately led to his demise at the hands of Jeremy Gilbert.
Kol escaped the destruction of the Other Side. His mother, Esther managed to resurrect him and place him into the body of a young witch named Kaleb Westphall. He temporarily aided his mother and his recently resurrected brother, Finn, but quickly followed his own agenda.