Joan Luss was one of the four "survivors" of Regis Air Flight 753.
A successful junior partner with a Manhattan law firm, Joan Luss was intensely ambitious, to the point where she regarded her own family, especially her children, as inconveniences, that she had to maintain for the sake of appearance. Her Haitian housekeeper/nanny, Neeva, privately reflected that her employer was so devoid of maternal feeling that Neeva often felt that she was taking care of three children instead of two.
Joan was flying back from a conference in Berlin, where she had thoroughly enjoyed her time away from her husband and children. After the tragic deaths of the rest of the Regis Air, Joan immediately began scheming a massive class-action lawsuit on behalf of herself, the other three survivors, and the victims' families, one which she envisioned would make herself and her firm so rich that she would soon be promoted to senior partner, and move her family to an even larger, richer home.
Eager to start this process, Joan applied legal pressure to have herself and the other three survivors released immediately, insisting she felt fine, despite Ephraim Goodweather's warnings that they needed to be kept in quarantine.
It is probable that the Master deliberately chose Joan and the three other survivors, knowing they would insist on leaving the CDC's custody and return home to spread the Vampire contagion among their family and neighbors. This helped sow confusion among the New York authorities, even as the "dead" passengers revived as vampires and began spreading the disease as well.
Within a day and half, Joan turned into a vampire, causing Neeva to flee the house with the two Luss children. During the day, Joan slept burrowed into the fresh dirt of the "European-style wine cellar" in their basement, and during the night, she hunted her children and infected the other members of her neighborhood.
Her ultimate fate is unknown.
In the TV series, Joan Luss's background and story are largely unchanged, except she is also seen meeting with Gabriel Bolivar, to ensure his participation in the anticipated lawsuit against Regis Air. She was killed by Vaun.