Who is Zdena from The Book of Laughter and Forgetting and what is their importance?

Zdena is the counterpart in Mirek's story, Zdena's once-close relationship with Mirek gives her power and control over his history. She holds onto their relationship as she becomes a member of the political party in which he is so powerful, reminding everyone that she and Mirek used to be a couple. After Mirek leaves her and shows he is embarrassed by her, she lives to have him remember their relationship, referring to situations that remind him and others of how close they once were. When Zdena witnesses the Russian tanks roll into their city, she rejoices because she knows Mirek will finally lose his power and ego. She shows him what faithfulness is when he is at his lowest point and her reason for living is revealed.