The Brotherhood of the Cloak was a group of all the non-novice wizards and sorcerers within the city of Mulmaster. Created for the near-singular purpose to control the power of magic within the city, all arcane spellcasters with any signifigant experience were required to join the Brotherhood under penalty of exile. Regardless of this consolidation of power, the Brotherhood was tasked with the protection of the High Blade (currently Rassendyll Uoumdolphin).
Along with the many regular members of the Brotherhood of the Cloak, there are 35 higher-up members referred to as the Senior Cloaks.
As only foreign visitors were allowed to cast spells within Mulmaster, some representatives living within the city, such as members of the Red Wizards of Thay or magic-wielding Zhents, are not required to join the cloaks.