In the Time of Dying Stars, countless children warped by the black rain were slain after birth as monsters and hellspawn. A special one lived, to her dismay.
In addition to the Thieves' Guilds, there is a hierarchy that all thieves are part of. Rank is based on skill, and can be raised or lowered at any time. The Queen of Thieves, the greatest living thief in the world, is the ruler. Guildmasters answer only to her, and she answers to no one at all.