She had brown eyes and long black hair which was going white at the temples.
Being a Sitter in the Hall for a time means that Jarna was also a high ranking sister and a strong channeler by Aes Sedai standards. In TWoTC her level is described as 18(6).
She participated in the torture and murder of Tamra Ospenya.
She died shrieking and screaming over a period of ten days. The use of this ter'angreal, or even how to activate it, remains unknown. Alviarin is appointed after her to take over the Black Ajah.
She was well-loved and respected by many Aes Sedai, seen as a model of virtue. All of the Tower and those who could reach Tar Valon in time attended her funeral where they buried what remained of her after her ordeal in the ter'angreal.