Yiyú, also known as Black Jade, is the former tiger to call of one of the Harlequin. She is delicate, petite, and Asian with long straight, shining black hair. She can fit under Anita's arm like Anita can fit under most of her boyfriends' arms. Yiyú had been severely abused by her former master, who used pain to control her. She remains in St. Louis with Anita, and although she can fight and is fearsomely good, the centuries of abuse have left her with the mentality of a victim. She makes Anita "heteroflexible" rather than heterosexual.