Fistandia

At some point in time, Fistandia was a presumed regular of Candlekeep. She had a specific room in the Pillars of Pedagogy reserved for her studies. The party learned that she hid a secret portal in that room to Her Mansion.  
The party presumes that she is still alive, because her Homnunculus Cumin is still alive in her mansion, though she hasn't been seen in quite some time.
She knows the Mordenkainen's magnificent mansion spell, and used her own additional enchantments to make the mansion permanent. She also knows how to create Homunculi.