Who is Az and Maddy from Uglies and what is their importance?

Maddy and Az are David's parents. Maddy was a doctor in the city where Tally lives, one responsible for turning young uglies into pretties. While researching a possible anesthesia side effect, Maddy and her husband, Az, discovered that many patients who underwent the pretty operation came out of it with lesions on their brains. As they continued to investigate, Maddy and Az realized that these lesions were intentionally inflicted on patients as part of the operation to make the patients more docile. Maddy and Az's research was confiscated before they could figure out how the lesions were made and how some of them were healed in patients who chose jobs that required them to be quick thinkers. For this reason, Maddy and Az left the city and founded the Smoke, a safe place where they could continue their research in secret.