Zesstra was the third daughter of Matron Mother Jyslin Aleanrahel. One day, patrolling near Ched Nasad, she found the Gorothir's Girdle, a sacred Sharran artifact, on the skeletal remains of an alhoon. This caused Zesstra's conversion to Shar and she also started a small cult inside the city. In 1370 DR, finally Jyslin discovered the heresy of her daughter but waited for the right time to expose her.
However, the destruction of Ched Nasad during the Silence of Lolth ruined the plots of Zesstra's enemies. On the contrary, she survived and expanded her cult by recruiting new members from the survivors. Her growing power, however, exposed Zesstra's failings as a cult leader.
With no grand schemes in mind, she plotted only to get revenge on her enemies. Unable to ruin them any further thanks to the city's destruction, she directed her followers to kill all her enemies. However, these actions also caused the death of many of her cultists. Thus, many of them tried to be assigned to missions far from the city to be no longer under Zesstra's control.