BIO:

Kol is the fifth child, and youngest (living) son of Esther and Mikael.  He is the younger brother of Finn, Elijah, and Niklaus; and the elder brother of Rebekah and Henrik (who is deceased).

During the Middle Ages, Kol, like the rest of his family, was human, up until that fateful evening when his younger brother, Henrik, was killed by werewolves when he and their brother, Niklaus, had snuck out to watch them turn.  It was because of this tragedy that their mother, Esther, an original witch, had decided to take action and turn her children into immortal beings, so that no harm could ever touch them again.  But though her intentions were good, she failed to take into account the very severe consequences of what performing such a ritual would bring.  Lacing their wine with the blood of a local girl, Tatia Petrova, the proginator to what would become the infamous Doppelganger line, and love interest to Niklaus and Elijah, she bound them together, using the power and life-force of the White Oak tree to bestow upon them the vampiric curse.  Driving a sword through each of their hearts while they slept and promptly forcing them to drink human blood when they awoke scared, and confused, Mikael sealed the deed, thus turning them into the first Vampires. 

• In life, Kol had a head for reckless behavior and irresponsibility. 
• He looks up to his older brothers, even though he would never admit it as fact. 
• He’s stubborn, and cares very little for the opinions of others.  When it comes down to it, he does what needs to be done, and it’s usually his way. 
• He’s extremely impulsive, and his uncontrolled bloodlust makes him one of the most unpredictable of his family.
• Without warning, he can go from very cordial and charming, to aggressive and direct in a matter of seconds.  
• Despite his arrogant nature, he is somewhat needy toward the rest of his family, tending to prefer company when he goes out, and isn’t very independent.
• Can be mouthy and defiant. 
• Finds Mary Porter’s fascination with them amusing.