Iggwilv

Iggwilv was the adopted daughter of the witch Sora Kell, at which time she was known as Natasha "the Dark". She became known later as Tasha, before adopting her alias of Iggwilv, although it was not clear whether any of those was her original name. It was at that early point that she was credited with inventing the Tasha's hideous laughter spell,[4] which by the early years of Galifar was commonly used throughout Khorvaire as a security measure against burglars, usually coupled with a glyph of warding cast on rooftops.[16]
For a number of years, Iggwilv served as a member of the first Arcane Congress alongside Mordenkainen under the moniker Tasha. In those years she was fantasized to be a consort of the famous wizard, something that he was unlikely to refute, Tasha was a vain sorceress of prodigious skill. Her most famous battle was against the rakshasa Mordakesh, who it is said she banished to a pocket dimension for over almost 1,000 years. Tasha, for reasons unknown, never returned to Arcanix after the Citadel defeated the rakshasa warrior.
Eventually, Iggwilv moved to her own Domain of Delight, known as Prismeer, in Thelanis, where she ruled from the Palace of Heart's Desire, in the guise of Zybilna. She was eventually betrayed by three other adopted daughters of Sora Kell: a group of Hags known as the Fetid Gaze, who used the magic of Iggwilv's Cauldron to transform the witch (and many of her palace's other inhabitants) into creatures that furthered the hags' plot.