Biography

As a child, she was used by her father for her powers. He forced her to use her ability to make Vanya forget she also had powers. This is a major plot point in the series.
She had a romantic relationship with Luther throughout her life, beginning at young age, but continuing after they met again at Reginald Hargreeves's funeral

Previous to Episode 1, she married Patrick, on whom it is implied she used her powers to initiate their relationship: 'I heard a rumour that you love me'. She has a daughter named Claire with Patrick.

Her marriage broke down after Patrick witnessed Alison using her powers on their daughter, after which he gained full custody of Claire. In this way especially it is clear that Alison began abusing her powers for personal gain and ease of life, her awareness of which acts as a motivator for her behaviour, particularly towards Vanya, throughout the season.

Personality

Allison is a determined woman with a kind heart and strong values. She has displayed her kind-heartedness on many occasions, particularly with her sister Vanya. She welcomed Vanya home, despite the book she wrote and even stated that she was glad Vanya had come.

Allison is also a very emotional woman, often being driven out of her feelings instead of rationalizing, such as when she went to confront Harold Jenkins on her own. She can also have the tendency to have outbursts at those who catch her in a bad mood. However, she is not completely hysterical, as she does give thought to her actions and reflects heavily, most notably on the use of her power. After being caught using it on her daughter and losing custody, she seemed to swear off using it, refusing to do it even during a confrontation with Cha-Cha, a highly skilled assassin.

Allison seemed to abuse her power of suggestion in her childhood and as a young adult, using it to advance her career, manipulate those around her, and even force someone to love her. This shows a deep insecurity in her, and her actions seem to haunt her consistently, causing her to act impulsively to avoid thinking about her regrets. She is strongly against using her power, even when her life is endangered. She shed tears when Vanya began to lose control, begging her not to make her use her power.

Despite everything, Allison has a deep love for her siblings. She goes especially out of her way to show love toward Vanya, seemingly as a way to make up for the cruel way she treated her as a child. She even forgives Vanya instantly after she almost kills her, and smiles warmly at her during her concert.

Powers and Abilities

Mind Control and Manipulation:
By prefacing a statement with "I heard a rumor," Allison can compel people do whatever she desires. Although she initially abused her power by using it for personal gain, her ex-husband, Patrick caught her using the ability on her daughter, Claire and she realised her use had been exploitative and stopped using it unless she had to.
Limitations:
Standard auditory and vocal range limitations. In order for her power to have effect she must be close enough to a subject that they can hear her.