She is the primary antagonist of the first story in 1:35 AM, titled the same as the book itself.
Ella is the main antagonist of 1:35 AM, the first story of the book by the same name. Ella is found at a garage sale by Delilah, a young woman dumped by her boyfriend who loves sleeping and has various issues waking up to go to his job at a diner. Delilah sees her as very similar to Emma, the child she once thought to have with her ex. Discovering the doll could function as an alarm clock, she buys her and sets her on 1:35 PM. When Delilah discovers she's not working, she left Ella in the garbage. The following night Delilah is awakened by strange sounds at 1:35 PM, and she starts thinking she accidentally sets the clock at 1:35 AM. Delilah tries to find Ella but she disappeared. With an online research, Delilah finds out Ella was a toy line produced by Fazbear Entertainment whose production was stopped in the 80's for unknown reasons and that a man named Phineas is looking for the doll, interested in his "energy". Delilah keeps being awakened at 1:35 AM and to see Ella around her. She tries various methods from preventing this from happening, like sleeping in the car or with a friend, but Ella always finds her and Delilah seems to be the only person who is able to see her. She tries to take on the night-shift at the diner she works at, but she keeps seeing Ella, and is fired for panicking. Now completely insane, Delilah finds an abandoned factory and she climbs inside a vent, until she gets stuck. Delilah is convinced the doll will never find her in that place. What happens after that is unknown, but it's implied Delilah will die by starvation.