Katie Featherstone (b 1979/1980) is a protagonist in Paranormal Activity and later an antagonist, she is the daughter of Julie Featherstone, older sister of Kristi Featherstone and the girlfriend of Micah Sloat.
Katie (aged 9) lived with Kristi (aged 5) and their mom and step dad Julie and Dennis in Santa Rosa, CA in September 1988. Kristi made an imaginary friend who she named "Toby" at first everybody thought Kristi was going through a phase and she would stop having an imaginary friend but it turned out Toby was in fact real, he was a demonic entity. Toby soon victimised Katie by violently dragging her out of bed in order to make Kristi agree "to do it" and the family fleed to Grandma Lois's in Moorpark, Toby followed them and after the coven had attacked the house Dennis found Katie standing over her mother's body and turned around to attack Dennis and went upstairs with Kristi and Grandma Lois (Paranormal Activity 3). Kristi gave birth to a baby son, Hunter, when she was adult and Katie often visited with her boyfriend, Micah. Toby returned and they discovered that the coven had made a deal to hand the next male born into the family to Toby and Hunter was the first male born since the 1930s, Toby was passed onto Katie and after the haunting she was possessed, killed Micah then went round to her sisters home to kill her then take Hunter (Paranormal Activity 2). Katie (partially possessed) moved into Henderson, NV with her "son" Robbie (who she acutally abducted and is too possessed) Robbie is placed into the Nelson's care and in the end Katie/Entity broke into the house and killed Alex's mom, Toby finished off Doug and Katie killed Alex before leaving with Robbie and Wyatt/Hunter (Paranormal Activity 4).