Rei
レイ
Rei is the middle ground of the Shuffle Sisters, being neither youngest or oldest. She seems to be most fed up with their trio which is rather unorganized and unable to sync properly with each other. She verbally expresses wishing to disband the Shuffle Sisters, though is shown to be rather kind and willing to do the common good otherwise.
Rei is revealed to be a phantom thief alongside Ai and Kira.