Juliet was born as the fraternal twin sister of Eva Violet from a one time relationship between Harriet Violet and Aaron Goldie that Aaron can barely recall. Harriet married Adamska Violet before giving birth to the twins, so he was legally recognized as their father. She was the half-sister of Morris Goldie, Chris, Lorie Goldie, and Cain Violet.
With the truth of her birth unknown to everyone except her mother, she was set to be betrothed to Morris in a political marriage to bind the Violet and Goldie families, which sets the events of the tragedy.
Due to Ritsuka Fujimaru's consciousness being sent into that of Juliet's friend, Ritsuka is unable to comprehend all of the sensory data in regards to humans through that connection. Ritsuka views them as Servants contracted to them, Violet appearing as Stheno. The assigned Servants may have some connection in terms of personality, but it is possible for key traits of the person to be confused due to the process. In the case of Violet, her mother Harriet takes the appearance of Euryale, Stheno's sister, and her sister Eva takes the appearance of the motherly Raikou, which greatly confuses Ritsuka for the majority of the incident.