The Guild Mage:
Guild Mages hold a special niche in the criminal underground. As a mage with specialized skills, they are able command high prices for their services and are often afforded a breadth of autonomy and privileges uncommon in the underworld. Guild mages commonly find themselves crafting potions of invisibility, fencing magical items, and appraising the odd trinket. Some guild mages have also been known to hold items of value in secure escrow and acting as a broker between parties. More adventurous guild mages, (for the right price) will even provide special services on site.
Since guild mages typically operate in large cities while servicing multiple competing factions, they have mastered of the art of being loyal to no one while being loyal to all. This delicate balance requires a killer smile, a great deal of trust, neutrality and diplomacy. Guild mages value their underworld reputation above all. Although the services of a guild mage may seem high even by underworld standards, this premium buys absolute anonymity and rare honesty in their dealings. This does not go to say a guild mage will not sometimes act upon information of privy for personal gain, but certainly never to the detriment of a client.
Thieves Cant, Appraising
Subtle casting – The Guild mage through years of practice has learned how to disguise or otherwise obscure his castings. A skilled guild mage can effectively cast spells without being noticed. Of course no amount of subtle casting can disguise the source of a Burning Hands spell, but it may allow for a nasty surprise.
Reputation – Guild mages value their reputation above all other things. If there is honor among thieves, it is among the guild mages. Guild mages will not cheat or steal from other thieves or underworld business contacts. Because of this they often become the epicenter for the trade of illicit information, goods and accessories to numerous questionable activities. With this often comes unwanted attention from various “interested” parties, making the lives of a guild mages a walk on the razors edge at times. Guild mages that have their reputation compromised will be forevermore labeled a “Rat” and shunned by the underworld or worse.
It is not uncommon for a guild mage to operate through proxies and agents, real or fabricated in the hopes of deflecting uncomfortable challenges to their reputation.
Above courtesy of Nomara