Book: DS9: Soul Key by Olivia Woods

Following on the events of Fearful Symmetry, Soul Key takes place in both ours and the mirror universes. Illiana Ghemor, who had her life and identity taken from her as a surgically altered operative of The Obsidian Order, is mad and bent on revenge. Her vengeance is not confined to her own universe, but to all universe in which Kira Nerys still exists. Like all MU stories, one of the most enjoyable aspects of this story is seeing dead characters brought back to life and familiar characters react to a different life and environment.