Zastava's official character description states that she is a rationalized surrealist: she puts her faith in rational actions, and her thoughts are backed up with solid reasoning and realistic observations. However, she does have interesting hobbies that are not quite rational, one of which is finger nail painting. Each one of her finger nails have been painted with a different fragrance (She even offers to paint the Commander's nails). Her overall personality is calm and obedient.
Zas's costume "Queen of the White Pieces" describes her side story interactions with the Commander during 2018's Anniversary Glory Star event.
Costume story: Queen of the White Pieces
A squadron of T-dolls were chosen to perform a covert operation to infiltrate a formal party, and protect a large diamond from being stolen by the infamous "404 Thieving Group". Zas was chosen to be one of the T-dolls of the defending squadron and wore her "Queen of the White Pieces" dress to the party.