Not much is known for certain about the cult.
They are said to hail from distant Azzazuum, where once there was a violent nation of slavers, oppressing all they conquered.
Those under the heel of the empire were united by a figure known as Nor Vul, who spoke of Kal'Tar, the Scorpion In Waiting, a vengeful deity who would wait for the right moment to strike down those who deserved it.
The people organized, and when the right moment came, they decapitated the empire's leadership - and literally decapitated the sorcerer-king that ruled over it.
The nation faded away, disappeared into myth - but the Cult of Kal'Tar is said to exist still.
Now, followers of the Cult can be found all over the Northern Realms, living in the shadows as assassins. While they still seem to honor their history, and claim that they only deal death to those that deserve it, there are also many that believe the story of their origin is just a fable to justify their actions.