"Sister" in Japanese has two kinds (different characters but same sound - NHE-SAN).
-姉さん means your elder sister that is blood-related to you.
-姐さん means an elder woman that is not blood-related to you but you like and respect like your sister.

"My Sister series is the second definition. It also means Japanese lady mafia boss or boss's wife. The inspiration of the series was from Japanese Mafia movies. I'm an animal lover and all my work has one or multiple wild animals"  -Yumiko Kayukawa

Sisters have a total of 3 prints being released in summer of 2023, fall of 2023, and winter of 2024.