An enchantress is usually defined as a magician, sorcerer, enchanter or wizard.I think "Empress" is a typo for "Enchantress."
For author Maggie Anton, an enchantress is also a sorceress or a woman who practices magic. Anton explains on her blog that when she was preparing to write “Enchantress,” (the sequel to “Rav Hisda’s Daughter”), she and a rabbi colleague went through “the entire Talmud again, tractate by tractate, searching for every mention of demons, magic, and enchantresses. We found far more than I expected; some stories were quite fantastic.”
“Empress” features Hisdadukh, the daughter of Rav Hisda, and is set in Babylonia from 299 C.E. to 359 C.E.
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More on Anton, this latest book, and her earlier novels is here and links.