Xister has long, waist-length hair that is two-toned, with the right side of her hair being an ash blonde, and the left side being black. Additionally, a single strand of her hair is dyed light blue. She wears a black cap featuring a white cross in the center atop her head. Upon removing the hat, she is shown to have two black horns. Her upper face is sometimes obscured in shadow, yet her eyes remain visible. She also appears to have scarring around her eyes and on her forehead.