David was originally introduced in 1987's Lost Boys; he is being modified to fit into the TVDU

Welcome to Santa Carla, the so called murder capital of the world.  It was also the stomping grounds of David Power, who grew up in a town where people inexplicably disappeared in droves.  He had a troubled upbringing, one of three children to a single mother who couldn't keep food on the table.  By the time he was in his teens, he was running the streets of Santa Carla, falling in with other youth that also were looking for an outlet for their pain.  Petty crime and being a general pain in the ass followed --- but what they didn't know was they were being stalked by one of the reasons Santa Carla was known for death. 

A vampire. 

This particular vampire (calling himself Max at this point) was drawn to those who seemed lost and in need of guidance.  Max turned David first, making him the unofficial leader of the little gang.   From there, he instructed David to turn anyone else who seemed to need family.  David immediately turned the rest of the gang (Dwayne, Marko and Paul).  In Max's mind, he would one day amass a following of 'children' that he would care for eternally.  David targeted Star, a runaway and even considered turning Laddie, a young child that Star took under her protection.  

Maybe they would have all lived as a 'happy family' feeding on the people of Santa Carla if it wasn't for the Emerson and Frog brothers.  After David tried to turn Michael Emerson, his brother with the help of the Frog brother fought back, killing Marko, Dwayne and Paul.  This lead to David losing his cool and in a final show down with Michael, he was impaled with a set of antlers.  They thought this was good enough to kill David but since it was not wood, David survived.

Since then he has lived his life perpetually stuck in the decade of his youth, the 1980s.  He has not turned anyone since he lost his brood, but he is starting to feel the loneliness that drew him to Max in the first place as a human.  He would like to have that kind of connection again and is looking to rebuild the so called Lost Boys. 

Please note that David's canon is mostly based on the movie but he will have the same powers and limitations as a vampire in the TVDU.