A similar entry appears in the Wheel of Time Companion confirming the information available in the main story arc.
Unless stated otherwise, all information herein is taken from Towers of Midnight, Chapter 49.
Oncala is Aviendha and Rand's granddaughter, her mother is Padra. She is proud of her heritage from the Dragon and resents the fact that the Andoran royal line also claims the same heritage as though it makes them equal to the Aiel. Forty years after the war with the Seanchan began, and Rhuidean has fallen to the Seanchan, she and Hehyal trick Talana into joining their war against the Seanchan by giving them a plan, stolen from the palace in Ebou Dar, for assasinating the Andoran queen. They do not tell her it is a contingency plan in case the Andorans join the war.