Ellie Quinlan is a 17-year-old teenage girl from Branson, Missouri. We meet her in novel Bloody Bones, when Anita is invited to the crime scene of Ellie's murder and turning into a vampire by her boyfriend Andy. Ellie's death is one of the events that triggers Anita's involvement with the vampires of Branson.
Ellie has brown eyes and thick, black hair that she wears curled and styled by hair gel for her tryst with Andy. Her legs are long and her breasts small and well formed. When she lies on her deathbed she's naked except for a black teddy that barely circles her waist at that point, and her make-up is smeared. Later, in the cemetery, she's wearing a long, black dress that she rips in her impatience to feed. Her legs are bare underneath.
Anita is called to the scene of Ellie's murder at the Quinlan house in the evening of St. Patrick's Day (March 17th). The sheriff overseeing the crime scene originally assumes that a strange vampire attacked, raped, and killed Ellie when she was getting ready to bed. He calls her a good girl who was never in any trouble, being found parked with a boy or out drinking. Anita points out that the bite wounds at Ellie's inner thighs are days old, and that she's clearly been paying attention to her appearance before going to bed, and has had to invite the vampire in -- and that by all likeliness Ellie never planned to stay dead, but to rise as a vampire, although she probably didn't plan on getting left practically naked and spreadeagled on her childhood bed for the duration. Regardless, she's still underage, so even with her consent it's a murder.
Unfortunately for Ellie's plans, her parents are very religious and insist on having her staked in order to save her immortal soul. Anita refuses to do it right away and even tries to talk them out of it, to at least wait for a day to let the thought sink in, but they refuse to hear anything of the sort or believe that anything that happened to their daughter might have been consensual. Anita later learns from Ellie's brother, Jeff, that Ellie's boyfriend Andy disappeared two weeks ago but Ellie hasn't seemed to be very torn about it despite being serious about the relationship. Ellie's father is under the impression that it was never serious and that he had put a stop on it, but Jeff knows that they just got better at sneaking around.
Later that night, after getting a warrant to serve, Anita leads a group into the woods after Andy. While they are gone the house is attacked despite precautions and both Jeff and Ellie's body are taken, prompting the Quilans to threaten to sue Anita. Another group of vampires attacks Anita & co., and Andy presumably dies in that attack.
Following Andy's death, Ellie answers to Xavier as her Master, since he's the one who turned Andy. When they arrive to the graveyard that is the center of the events of the third night of the novel, Xavier insists her name is Angela and she's two years dead despite all the evidence to contrary, even after Anita points out they can never hide Ellie with such lie and that people will recognize her. She hasn't fed yet for the first time and is practically senseless from the hunger, and would attack anyone or anything if Xavier didn't have a hold of her. She shows no hints of recognition towards his brother who is also present. She and Xavier end up drinking already unconscious Ms Harrison the rest of the way to death. Afterwards Ellie runs away with the rest of the vampires who don't know how to fly.
Later that night, at Serephina's house, Ellie looks content and almost alive, and like she's enjoying being undead, even without Andy, although she still hasn't recovered her previous personality. When the fighting starts she's too freshly risen to be able to withstand the crosses and stays frozen in place. After the crosses are hidden she is one of the vampires who pile on Jean-Claude to keep him in place.
When Anita wakes up in Serephina's coffin the next day (March 20th) Ellie is curled at the base of the stage of Bloody Bones bar. After getting out of the coffin Anita has to step around Ellie to clear the stage. During Anita's confrontation with Magnus Bouvier some of her blood splashes on Ellie, making her the first vampire Anita discovers she can control like a zombie during the daytime. She makes Ellie grab Magnus to keep him from stopping Anita from escaping. Ellie doesn't let go even after Magnus stabs her, although she screams in pain. Magnus tries to follow Anita outside into the sunlight regardless, and Ellie burns to death with white-hot flames in the parking lot. She melts into the flesh of Magnus, who can't pry her arms away, and he burns to death with her while Anita escapes. We later learn that Ellie's brother Jeff is also already dead at that point, and on his way to becoming a vampire, although he never gets a chance to do that as the whole building is burned down around the remaining Branson vampires only a few hours later.
Afterwards the Quinlans have only Anita's word that Ellie is dead, as there isn't enough left for recognition after a vampire burns. Anita doesn't tell them how Ellie died, though, as using necromancy to commit murder would earn Anita herself a quick death sentence. The Quinlans are still determined to sue Anita for not staking Ellie when they demanded so, and blame Anita for causing the loss of their son as well.