Sully was born and raised in the slums of North Ambria.
She escapes to Crossbell City where she broke into the Arc en Ciel theatre during one of performer Ilya Platiere's rehearsals. Sully resented the unfair gap between the glamorous Ilya and her own miserable life, so she repeatedly broke into Ilya's apartment in Hotel Raisins at The West Street.
Princess of the Stars
When she was caught red-handed by the Special Support Section, Ilya considered Sully a great fit for her team and took her into the Arc en Ciel troupe. Sully was given the role of "Princess of the Stars" in the play Golden Sun, Silver Moon.
Sully went through a period of depression after the Crossbell City Attack, where Ilya had protected her life at almost the cost of her own life. Fortunately, Ilya made a miraculous recovery so she could dance alongside Sully and Rixia Mao during the Imperial occupation of Crossbell.
Zero and Ao no Kiseki