The Nightsister of Dathomir who bore Asajj Ventress was a female Dathomirian who resided on that planet at a time preceding the Invasion of Naboo.
Asajj Ventress's mother, a Dathomirian Nightsister hailing from Dathomir, belonged to the Nightsisters group headed by Mother Talzin. In 50 BBY, she gave birth to a daughter, Asajj Ventress. To safeguard the clan, she had to relinquish her to the Siniteen criminal Hal'Sted, a decision causing distress for her and the clan's leader, Mother Talzin. Growing up, her daughter later returned to the clan and also became a Nightsister.