A little Russian girl, nicknamed Katja, at first she appears to be a cute, helpless ten-year old, whose doll-like features and childish manners, such as referring to herself in the third person, granted her admiration from many that encountered her.

Indeed, she is far from innocent, and especially, she is not ordinary. In fact, she is a Qwaser whose element is copper, with which can freely control any copper-made material, such as electrical wires to direct flows of electricity as she sees fit, or generate massive amounts of liquid copper and solidify it as she pleases.