Dr. Martinez is a veterinarian who lives in Arizona with her daughter, Ella, and dog, Magnolia. She has curly black hair and brown eyes, and is Hispanic

In The Angel Experiment, Max locates Ella's house after being shot in the shoulder and wing. Dr. Martinez helps Max heal, and gives her an x-ray. Max's bones and muscles were repairing, but Dr. Martinez discovered a microchip that could be used to track down the flock. Max grew fearful that this was why the Erasers were finding her flock so easily.

In Saving the World and Other Extreme Sports, Jeb finds Max in a dungeon and tells her that she is the child of he and Dr. Martinez. This leads to the fact that Max is the half-sister of Ella and Ari. Also in the third book, Max visits Dr. Martinez's house with Fang to get her microchip surgically removed. Dr. Martinez puts Max on Valium (during which she first admits her feelings for Fang) and completes the surgery, but Max temporarily loses the use of her hand.

In The Final Warning, Dr. Martinez informs Max that she told a friend about the flock, and that the friend wanted Max to work with a group of good scientists specializing in Antarctic studies. The flock then helps the scientists with their research.

In Max, Dr. Martinez lets the flock stay at her home once they are finished doing air shows in Mexico City. Later in the novel, she is captured and held hostage underwater. The flock goes with some of the scientists whom they met in the previous book to Hawaii, the closest land area possible to where Dr. Martinez was being kept. With the aid of radioactive creatures dubbed "the Krelp", Max and Angel rescue Dr. Martinez and resuscitate her on land.

In Angel, Dr. Martinez defends Max once Dr. Hans Gunther-Hagen insist that Max should breed with another human-avian hybrid named Dylan.