Kei Sinclair is a blonde and active individual with the ability to shapeshift into a leopard, a power used to hunt and devour targets after initial engagement. As a member of the musical group The Pussy Cats, this identity provides cover for Sinclair's role in the assassin team known as The Midnight Panther. The group is managed by an elderly woman who is secretly a witch coordinating their assignments. Kei Sinclair operates alongside two other members, Sonya Sei and Lukish.