Who is Elaida do Avriny a'Roihan from A Crown of Swords and what is their importance?

Elaida is the Amylin at the White Tower. She is known for her angry outbursts. Elaida has visions and has seen in one of those visions that she will triumph, and her visions are never wrong. Elaida is trapped by Alviarin into pitting the houses of the Tower against each other. Elaida gives a secret mission to one of the Aes Sedai in the White Tower to find any who might be members of the Black Ajah.