Sister Oscar

Sister Oscar
Sister Oscar is a nun of the Sisters of Mercy. She is known for her prowess with swords and her ever-sparkling visage.

She appears to be of French descent as she is shown to switch to her native language when she becomes riled.

Relationships
Oscar and Catherine have been close friends since they were children. Oscar is evidenced to have romantic feelings toward Catherine and the two appear to have a long-lasting romantic relationship with one another. They were married, though it is currently unknown if they still are and simply hide it whilst living as nuns, or if they are seperated, as neither wear wedding rings. Catherine is also the first among the sisters to know that Oscar is a trans woman, due to them growing up together having both been adopted into the same household.

Oscar is mentioned to be the older sister of the twins. This could explain why she acts as their guardian and mentions that the two are "all [she] has left".