The "Nightsister Matriarch" was a female Human Nightsister, a native of the planet Dathomir, whose activities occurred during the era of the New Republic. During that time, she commanded a Nightsister group in an attack targeting the base on Dathomir that belonged to the Imperial warlord known as X1. The Grey Squadron of the New Republic soon became involved in the conflict. In the midst of this battle, the Matriarch faced Jedi Knight X2 and ultimately met her death at his hands.
The title "Nightsister Matriarch" was given to a light-skinned Human female Dathomiri Witch belonging to the Nightsisters on the world of Dathomir during the New Republic's reign. It was during this time that the Imperial warlord X1 created a facility on the planet for cloning experiments. After X1's departure, the Nightsisters, under the Matriarch's leadership, seized the base. While the Nightsisters engaged X1's troops outside, the Matriarch herself, mounted on a rancor, entered the base.
Sometime between 11 ABY and 19 ABY, X2, a Jedi Knight leading the New Republic's Grey Squadron, arrived on Dathomir seeking X1. After fighting their way through the Nightsisters, Grey Squadron reached the base's entrance. Sensing the Matriarch, X2 instructed his squadron to provide support at the entrance while he ventured inside alone. The Matriarch burst through a wall and attacked X2, but he managed to kill the rancor. Subsequently, she attacked X2 with her lightsaber and the Force, but the Jedi Knight was victorious and killed her.
The Nightsister Matriarch was a proficient user of the dark side of the Force, and her strong dark presence was felt by X2. She wielded a red-bladed lightsaber in combat and showed skill in telekinesis. Furthermore, the Matriarch could control her rancor, using it in her confrontation with X2.
The Nightsister Matriarch is featured as an enemy boss in the Nintendo DS version of the 2009 video game titled Star Wars Battlefront: Elite Squadron.