Fabia is a parody of iconic fashion designer Donatella Versace. She's a rival and often friend to Wilhemina, she says to have a child thats about 3 and 1/2. And is apparently married to an elderly Dmirti, well as far as we know from "East Side Story".
Fabia is a fashion/cosmetics mogul and former model who speaks in an Italian accent. She is also a single mother, carries her dog and her entourage around, and chain smokes. She threatens to pull her advertising campaign from MODE after seeing the draft which involves a car crash, which hits home for her because she has recently been involved in one herself. It is actually a set-up put together by Wilhelmina Slater and Philippe Michel, so as to make it look like Daniel Meade is responsible for authorizing it. When Daniel realizes he is being sabotaged, he turns to Betty (after turning her away the first time around) to save the campaign, and she comes through with a concept of her own involving mothers and daughters, using photos of Betty's late mother. Thanks to Betty, not only is the campaign saved, but both Betty's and Daniel's jobs as well.
Fabia returned in the episode "I'm Coming Out", convincing Wilhelmina, with whom she has a rivalry, to have duck semen injected into her face, only to learn she has tricked Wilhelmina into using the process. After Wilhelmina shows up at Fashion Week with a bloated face leaving her blind, Fabia laughs at her, seeing she has taken her phony advice.
The ongoing rivalry continued in the season finale, "East Side Story", in which she, in exchange for giving up a June wedding (she was going to marry Dimitri, the world's largest shipping magnate in order to get his money) to Wilhelmina, Wilhelmina gave up Marc, but changed her mind after seeing Fabia wanted Marc in her entourage in order to demean him in front of Wilhelmina, namely by ordering him to clean up after "Pichu made brown". After Marc mentions in passing to Wilhelmina he hopes her June wedding was worth it, it made her realize she did care for Marc and regretted giving him up to Fabia's entourage. Wilhelmina told Fabia she could have the wedding before hers, getting back Marc and scheduling wedding date to November.