Katryna lives a double life. During the day, she is the divorced single mother of a five year old daughter. At night, she takes on the role as Mr. Black. She is the boss of Seraphina, Zephyra and Nora and is the one who sends them on their assassination missions. Katryna comes from an extremely wealthy family and has no issues with sharing her wealth to the girls as a reward for a job well done.
Katryna has two rules: Always refer to her as Mr. Black in her presence and never call her old.