Gillian Casey

Gillian Casey is the main villainess of the 2014 movie The Girl He Met Online.

She is played by Yvonne Zima.

History
Gillian's parents died when she was a child. After that, she and her sister Bethanny were sent to live with Agatha, a foster mother. From her first day with her, Gillian was open about her resentment of Agatha, telling her that she'll never be her mother. Despite this, Agatha hoped that Gillian would grow to love her, but their relationship only deteriorated further, only worsened by the fact that Gillian was forced to stay with Agatha after she had a heart attack and was unable to work and provide for herself.

Gillian had a long string of bad relationships, doing further damage to her psychological well-being. She attacked one of her boyfriends with a bottle when she found out he was cheating on her and trashed the house of another after he ended their relationship. She also worked for an OBGYN, where her boss Harris began an affair with her, helping her out financially in exchange for sex.

Events Of The Girl He Met Online
The movie begins with Gillian trashing the house of her ex boyfriend Tony after he broke up with her over the phone. After that, she goes online to look for someone new. She finds the handsome and wealthy Andy Collins, who is the son of the founders of a successful advertising company where he also works. The two chat while Gillian is at work and arrange to meet for coffee.

At first, Andy and Gillian hit it off. Gillian is fantasizing about a happy life with Andy and Andy is certain that she's perfect. However, Gillian goes out of her way to avoid letting Andy see her at home, feeling her mother's house is "a dump". She also attacks Agatha when she finds out she wants Gillian to move out. Meanwhile, Tony's housekeeper finds the damage done to his home by Gillian and calls him in Estonia (where he's away on business) and plans to come back to deal with her.

When Andy invites Gillian to a business party, she steals a dress from a clothing store to wear to the event. But while there, she runs into the snobbish store owner Doty, who instantly recognizes the dress and subtly lets Gillian know that she recognizes it. Enraged, Gillian goes to the bathroom and punches the hand dryer several times, calling Doty a "rich spoiled bitch". She then has Andy take her home early, feigning an upset stomach. The next day, Gillian goes to Doty with the blouse (which she tore up after she got home) and claims it fell apart on its own and orders her to cover her debt, threatening to set her store on fire with her in it if she doesn't. Gillian then storms out, stealing a few more items on her way.

Tony confronts Gillian at her office, demanding she repay him for a painting in his house that she ruined. When Andy arrives, Gillian becomes desperate and gives Tony her car, promising to get him the rest of his money later. Tony accepts and Gillian tries in vain to convince Andy (who has already been getting suspicious of Gillian) that it's all OK. Needing to get the rest of Tony's money, Gillian arranges a date with Harris at a hotel. But while there, Andy's sister Heather arrives and spots Gillian kissing Harris.

Gillian sees Heather as well and rushes to explain what's going on. Heather expresses some sympathy, but still insists on telling Andy herself. Desperate and angered that (in her mind) Heather is trying to ruin her relationship with Andy, Gillian pushes Heather down the stairs, killing her. She then quietly goes back to her hotel room while a janitor discovers Heather's body. Meanwhile, Gillian drugs Harris and convinces him to give her the money she needs.

Andy is heartbroken by his sister's death and Gillian provides comfort. But during this, she's further pushed to her limit when Harris (having figured out that he was drugged by Gillian) forced her to quit her job. Andy listens to a voice mail Heather sent him before she was killed that reveals that Gillian had went to the hotel instead of on a trip to New York with her mother like she told him. He confronts Gillian about her lie, during which she reveals her true nature, taunting Andy that he's "only a boy, not a man" and about all she had done to put her life together and kept their relationship together while he just had everything handed to him. She warns him to leave before she hurts him and Andy leaves. As Andy goes to the police to find out more about Gillian, Gillian returns home and is confronted by Agatha for her lies. During a mental breakdown, Gillian attacks Agatha and tries to strangle her to death, shouting that she won't end up like her. The police and Andy arrive and stop Gillian before she can kill her. As she's taken away, Gillian yells to Andy that he'd never done anything for love. While being interrogated, Gillian tearfully tells the detective that she didn't kill Heather for being disgusted at her actions with her boss, but because she was threatening to ruin her relationship with Andy.

It can be inferred that Gillian was then sent to prison for Heather's murder and the attempted murder of Agatha.