Who is David from Uglies and what is their importance?

David is a young man who lives in the Smoke and actively recruits uglies from the cities. David's parents founded the Smoke after they learned, as doctors in the same city where Tally lived, that the initial operations left a lesion on the patient's brain that made them more docile. David falls in love with Tally almost immediately upon meeting her because he believes her to be a very brave and strong young woman. David tells Tally all the secrets of the Smoke, unaware that she is a potential threat to the community.