Who is Bud from The Diamond Age, or, Young Lady's Illustrated Primer and what is their importance?

Bud is the boyfriend of a woman named Tequila and presumably the father of Nell and Harv. He is a "thete", an individual not associated with any tribe, as well as a criminal. He is unable to join or work for any other group; therefore, he feels like he has to act alone. He is obsessed with his artificially muscular body and decides to become a hard criminal to survive.