Iggwilv
Iggwilv is a malevolent female archmage originating from the Greyhawk setting. She belongs to that small, elite club who represent characters originally played by Gygax and his buddies during the founding of Dungeons & Dragons, such as Murlynd, Zagyg and Mordenkainen. Her in-game lore is that she adventured with them, learning much about magic in the process, but ultimately revealed herself as evil and betrayed them, going on to become one of the Great Wheel's foremost experts on black magic and demonology. So much so that Dragon Magazine titled its articles on various demons and Demon Princes as "The Demonomicon of Iggwilv", after a literal book she wrote on the subject.
About a century before the Guide to the World of Greyhawk 576 CY, so 480ish, Iggwilv conquered Perrenland and looted the place for her demonological research - for instance, imprisoning the Demon Prince Graz'zt, for her personal manservant and boytoy. A decade later Graz'zt got free, and in the process of banishing him back home, Iggwilv's coterie betrayed her and looted "her" (mostly Perren) wealth. Perrenland freed itself immediately afterward.
(Literal) Legacy
Iggwilv is the mother of the cambion Iuz, who later ascended to an actual god on their homeworld of Greyhawk. She gave birth to him during a period she kept Graz'zt bound. He later repaid the favor by keeping her as his slave. They are currently in mutual tsundere with one another.
Another daughter, who guards her vault under The Lost Caverns of Tsojcanth in eternity as a vampire, is (or was) Drelnza. This one was born human. We're not told if she was born before the Perrenland adventure and Graz'zt sexytimes, or afterwards.
It's rumored that she may be a daughter of Baba Yaga.