Maggie was born in 1832 in Ireland. She had difficulty dealing with authority, on a parental and community level; she was born with the gift to sense when someone was lying, and in those situations, she felt compelled to point out the lie. Her accuracy made people uncomfortable around her, especially close ones. Though this often led to punishments, sometimes quite severe, she did not relent her nature. Certain people thought of her as a devil because of her gift.
The Great Famine in the 1840s decimated her village, and her family was forced to leave for America in search of a better life. Her family didn't have enough money to transport every member and Maggie was subsequently left behind to take care of her maternal grandparents, mainly - as she knew - because her parents felt uncomfortable with her sensibility to lies. Siobhan and Liam found Maggie alone on the road to Cork, nearly dead from starvation. She was almost immediately able to recognize them as non-human. Siobhan, curious with her ability, offered to make her strong enough to live. Maggie sensed that she was telling the truth and so agreed. Siobhan's mate, Liam, was not convinced about having her with them, but Siobhan persuaded him otherwise. She deeply enjoyed their company because they were routinely honest both with themselves and each other. Over time, even Liam had warmed up to her.
Whenever they encountered another vampire or human, she could use her gift to sense their honesty, and so Siobhan and Liam trusted her judgment.
- Main article: Breaking Dawn
- "I know truth is on Carlisle's side. I can't ignore that."
- ―Maggie's declaration to help the Cullens.[src]
In Breaking Dawn, Carlisle and Esme seek the help of Maggie and her coven and ask them to go to Forks. Once they arrived in town, Edward and Bella tell them about their half-vampire daughter, Renesmee, and because of her ability, she is able to determine the baby was not an immortal child and that the Cullens are telling the truth about their innocence.
She later stands as a witness for the Cullens to try and save the child from the Volturi's accusation. When co-witness, Alistair, fled out of fear for the Volturi, she declares her determination to stay behind and help.
She, like the rest of her coven, returns to Ireland at the end of the story, after the situation was resolved peacefully. She gives Renesmee and Bella a hug before setting off with her coven.
In the film Breaking Dawn--Part 2, within Alice's vision of the batle, her decapitated body can be seen behind Alec for a brief moment shortly before he tackles Bella; thus, making her a casuality in addition to Carlisle, Jasper, Seth, and Leah.
Maggie is described as small, standing 5'2", thin and with bouncy red curls, and not as physically imposing as Siobhan or Liam. In the movies, her hair is brown but still curly.
Maggie is very righteous and believes in justice. Whenever someone lies to her, she will loudly point it out even when it got her into trouble, usually with authority, both on a parental and a community level, which punished her severely for it. This is why she feels comfortable with Siobhan and Liam because they are always honest both to themselves and to her.
Powers and abilities: lie detection
- Main article: Lie detection#Maggie
- "She had a gift for knowing when she was being lied to, and her verdicts were never contested."
- ―Bella, on Maggie's gift.[src]
In addition to her talents of a vampire, she is also gifted with the ability to sense when someone is lying to her. This power manifested from her potent ability to read people's lies as a human. This becomes very useful when helping the Cullens, as when the Volturi came for Renesmee and Aro was about to tell her she was going to be fine, and Maggie knew that he was lying.
According to The Twilight Saga: The Official Illustrated Guide, she can read a person's appearance or actions to know if they are lying as well. As a side effect to this gift, she would feel physically uncomfortable with any kind of deception.
As a human, Maggie was the child of an Irish family and was the oldest of her siblings.
Siobhan is Maggie's creator, and leader of the coven.
She found Maggie starving to death in Ireland, and she could tell that they were not human because of her power. Siobhan, fascinated with her ability and feeling pity for the young one, offered to change her into a vampire so that she will never feel hungry again, which she agreed.
After she was changed, Siobhan treated her like a daughter and Maggie is happy to have found someone who acts and speaks on their intentions.
Liam is Siobhan's mate, and therefore a prominent part of the coven.
Unlike Siobhan, Liam was initially reluctant to having Maggie in their coven (mostly because he did not want to share Siobhan's attention with the young girl). However, Siobhan managed to convince him to give her a chance, but he only agreed begrudgingly.
Liam eventually saw the usefulness of having a talented member, and began to accept Maggie as one of them and treat her like a sister.