Emily Sasaki Edit
As an infant she appears to be quite healthy, with a tuft of brown hair, and rosy cheeks. She is not seen as an infant in the rest of the film.
As a young child, she has brown hair in a short hairstyle, and her eyes are shown to be dark brown. She seems to be wearing a school uniform consisting of a white shirt, yellow vest, a red bow, and light pink skirt.
By the time she is seen again, she has matured into a teenager or a young adult. She has long brown hair into a ponytail, along with a satchel and uniform.
Her last appearance in the film, she has aged a few years. Her hair is significantly longer, resembling Marnie's childhood hairstyle at the ends. She seems to have stylish clothing along with jewelry. She is not seen again.
Not much is told about her, only that she was born two years after Marnie's marriage. After her father's death some years later, she is sent to a boarding school for elementary school, and can be thought the next grades after that as well. Once Marnie had come to take her back, she pushed past her and went into the car without a word.
Later, we are told the two never made up, and Emily ran away from home and got married. It was also revealed she was pregnant with Anna at this time. She later dies 1-2 years later from a car accident along with her husband, which we can only assume his last name is Sasaki. She is never spoken of again in the film.