Encyclopaedia WoT: Sierin Vayu

An Aes Sedai and the Amyrlin 979 to 984 NE, raised from the Gray Ajah.

She is very plump with a round face but she has hard eyes. (NS,Ch14)

The day after Tamra's death, the Sitters select Sierin Vayu as the new Amyrlin. This is two weeks after Moiraine and Siuan are raised to Aes Sedai. (NS,Ch14, TFoH,Ch15)
Sierin begins her rule with an iron hand firing all male clerks and ordering two sisters birched and three others exiled for a year. (NS,Ch14)
Sierin rules from 979 to 984 NE. (Guide)
Sierin dies mysteriously two years after Alviarin is raised to head the Black Ajah. The Black Ajah did not have anything to do with her death. In fact, Chesmal induces the Red Ajah to murder her. (ACoS,Prologue, WH,Ch10)

In New Spring
1. NS,Ch14 - When Sierin was raised to the shawl, many sisters were surprised that she chose the Gray Ajah instead of the Red.
2. NS,Ch14 - As Amyrlin she was a severe disciplinarian.
3. NS,Ch18 - When Moiraine sees Siuan she thinks that Sierin Vayu discovered their plan and sent Siuan to bring her back.
4. NS,Ch18 - Before she leaves the White Tower, Siuan leaves an anonymous note about the Black Ajah for Sierin.
In The Fires of Heaven
1. TFoH,Ch15 - Moiraine recalls that Sierin was Gray Ajah, but she acted more as if she were Red Ajah.
In A Crown of Swords
1. ACoS,Prologue - Alviarin wonders if Elaida had anything to do with Sierin's death. The Black Ajah did not.