As revealed later on, Ms. Fields was actually the daughter of Emily Burt, the alleged Talbot County Werewolf. The legend followed Emily's family years after her death, including her daughter; it came to the point that she changed her name to Ms. Fields in order to escape the backlash. At some point, she turned heel and began perpetrating several murders in the woods of Talbot County, Georgia, including (assumingly) Isabella's birth parents. The killings drove Isabella insane, and in the aftermath, Ms. Fields took Isabella in and forced her into becoming her cohort in her murderous quest.
In 1986 (the year the film is set in), the sadistic Ms. Fields instructed Isabella to lure her Columbus State University classmates into Talbot County's woods so that they could kill them one by one, with Isabella's reveal being cemented when she murdered Kenny. During their killing spree, both villainesses used clawed blades in order to continue the werewolf ruse, and it was after Isabella took Blake and Blair to a secluded home that Ms. Fields' official villainous reveal occurred. After the maniacal villainess set up Blair to be killed by her pack of wolves while the former was talking to the latter on the phone, beginning the aforementioned reveal, Ms. Fields entered her home in a fur coat and searched for Isabella, firmly establishing her true role as the deranged mastermind behind the murders. She then expressed disappointment in her unwilling henchwoman for allowing Blake (whom Isabella was in love with) to live, and after that, a fight broke out between the two women. Ultimately, Isabella turned on the gas and blew up the house, killing Ms. Fields and herself.