Appearance and Abilities
She is black haired with a white streak above her left ear. 5'4 tall, she had a coldly arrogant face.
She is from Kandor. Born in 924 NE, she went to the White Tower in 940 NE. She spent nine years as a novice and seven as Accepted, becoming Aes Sedai in 956 NE.
Fleeing the Tower
When the Liandrin's group of Black sisters left the White Tower, they took several ter'angreal with them. They first fled to Tear, but they are followed by Elayne Trakand, Egwene al'Vere, and Nynaeve al'Meara. They captured the three pursuing them, but Matrim Cauthon rescued them while he aided Rand al'Thor in taking the Stone of Tear.
Tanchico and Amador
Rianna and the others then fled to Tanchico, but Joiya Byir and Amico Nagoyin were captured. After arriving, they lived in a house that used to belong to a Darkfriend merchant. They then gained access to the Panarch's Palace and held the newly invested Amathera Aelfdene Casmir Lounault captive. Unbeknownst to them, they were followed again by Elayne and Nynaeve, who had been told where they were going by Amico. Elayne and Nynaeve freed Amathera and left as a mob gathered around the palace.
Somehow, Rianna and the rest escaped and went to Amador. There, Moghedien took over the group that Liandrin had been leading. Rianna accepted her instructions stolidly, with just a touch of relief in her eyes. Her mission was unknown.
The Last Battle
Regardless of what her task was or if it was completed, Rianna appears again at the Field of Merrilor in Alviarin Freidhen's company. Together with Alviarin and a number of Darkfriend Asha'man, she is lured into an Ogier stedding and taken a captive.