From the D&D and Planescape setting:
Grenpoli, the City of Diplomacy, located on Maladomini, the 7h layer of Baator, is domed, and access is granted only through one of four gates on the city's exterior. Entrance to the city comes after a thorough search during which all weapons are taken for the duration of a visitor’s stay. Strife and open displays of magical aggression are against the law, and those who break the law are slain immediately. The Political School of the Nine Hells, in Grenpoli, is where enterprising devilish nobility come to learn about treachery and deception.
The Arch-sophist Mysdemn Wordtwister is the fonder and the ruler of Grenpoli and the head mistress of the Political School. She is a erinyes devil and she is the most devious of the five sophists, the greatest teachers of the school. She is one of the few erinyes that never visits the Prime Material Plane, because her abilities are requested directly in Baator. She rules the city with the politic of the "iron glove covered with silk".


I really thought a lot how to design for her a dress modern (like a secretary) but fantasy style at the same time and with space for her wings.
That's the result. She wears glasses but only because they are a magic item (all devils have a perfect sight).

Here is the link to a bigger version of the pic
http://johndowson.deviantart.com/art/The-Wordtwister-68796221