Appearance and Abilities
Saerin is 5'6" tall and has olive skin and straight black hair that is graying slightly at the temples. She has a faint, faded scar on her left cheek and jaw, giving her a somewhat intimidating look. She is attractive but unlike her Brown Ajah sisters she is seen as quite fierce; scowling as well as any Warder. Saerin retains an Ebou Dari sense of honor and often carries a traditional curved dagger behind her belt, which she unconsciously fingers when angry.
Saerin was one of the strongest sisters in the White Tower with strength rated at 14(2) on the Power Strength Scale. This would have placed her in a position of political influence comparable to Pevara Tazanovni or Yukiri Haruna.
She was an innkeeper's daughter. She was trained by the Daughters of Silence, who recruited her in 796 NE, prior to coming to the Tower and was their only apprentice to become Aes Sedai. She joined the White Tower in 798 NE and spent twelve years as a novice and ten years as Accepted. She spent so long in her training because of her association with the Daughters of Silence, and was the only member who managed to become Aes Sedai.
Saerin was raised to the shawl in 820 NE.
She has been a Sitter for forty years, longer than any other Sitter in the loyalist White Tower.
She is one of the oldest known living Aes Sedai at the time of the Last Battle. She is 219 years old.
She remained loyal to the White Tower during the Schism  and somehow contributed to provoke it. In fact Doesine Alwain, Yukiri, Saerin and Rubinde Acedone, Sitters known for their rebellious temperament, were persuaded/manipulated to vote for the deposition of Siuan Sanche and then to raise Elaida a'Roihan as new Amyrlin Seat. They all regretted early these decisions.
She was one of the six Sitters whom Elaida gave penances to, despite (or perhaps because of) her being the most senior Sitter in age and tenure. She was given Labor, forced to work in the kitchens alongside the scullions. She was disconcerted to find that Laras, Mistress of the Kitchens, treated her exactly like a scullion - worked hard and called out for not doing work properly. Saerin did like Laras for that, as she considered it the proper attitude to have towards penances.
Saerin, along with Yukiri, Doesine and Talene Minly, followed Pevara and Seaine Herimon into rooms below the White Tower, where Pevara and Seaine ordered them to forswear all current oaths and then reswear the Three Oaths using the Oath Rod. They were then asked if they were Black Ajah. Saerin re-swore her Oaths and afterwards answered that she was not Black Ajah, proving she was not.
Of the three examined only Talene was identified as Black Ajah. Later, she found out that she was to attend a Black Ajah Supreme Council meeting where she suspected she would be murdered. Saerin hides her in a room in the lower basement of the White Tower.
Consorting with the rebel Amyrlin
She is in the White Tower basement when Meidani Eschede brings in Egwene al'Vere. Egwene tells them to continue hunting the Black Ajah but also tells them to remove the fourth oath they have placed on the Rebel Spies. Egwene also points out that when Siuan Sanche was deposed the action was unlawful because a member of the Black Ajah sat in on the proceedings, providing a bare minimum of Sitters required and making any action they took an unlawful action.
After Egwene is released from her cell, Searin finds her and relates to her that Silviana Brehon denounced Elaida over Egwene's poor imprisonment conditions. Egwene sends Saerin to summon the Hall of the Tower to try and remove Elaida or at least save Silviana from execution.
She takes charge of the Aes Sedai resistance against the Seanchan in the Battle of Tar Valon along the ground floors in the White Tower. Katerine Alruddin tries to unsurp her position but is reminded that she, Searin, is a Sitter while Katerine is not.
She stands with the rest of the Hall of the Tower to raise Egwene unanimously as the new Amyrlin Seat. She takes a rough census of the number of women who were captured by the Seanchan during the battle and provides it to Egwene.
Saerin is with Siuan Sanche when Jimar Chubain informs them that Rand al'Thor has entered the White Tower. During their way to meet with the Dragon they face and avoid a bubble of evil that is transforming a Tower corridor in a blood pool.
Giving and making a choice
Saerin is one of seven Sitters who take part in Nynaeve al'Meara's test for the shawl inside the oval ter'angreal. The testing is unusually severe, cruel even, and Saerin is heavily concerned and even furious afterwards at the others for making Nynaeve suffer so much. She is one of the four Sitters - the others being Yukiri, Seaine and Romanda - who think her worthy, thereby allowing her to be raised properly.
She arrives late to a secret meeting called by Hall of the Tower - she and other Sitters seen as Egwene's supporters were purposely left out. Saerin figured out Egwene's maneuvering to trick the Hall into voting for a proposal that would allow only Egwene to deal with the monarchy of the world, which includes Rand as he is King of Illian, while the Hall would take over prosecution of the war and deal with Gareth Bryne's army. Saerin supported Egwene in this and hinted to latecomers Doesine and Yukiri that they should vote in favor. In that same meeting of the Hall, Saerin voted in favor of the new rules and procedures in the Hall as outlined by Egwene, which included temporarily replacing a Sitter when she is absent from the Hall and that no meeting of the Hall can commence without all Sitters and the Amyrlin Seat being present.
The Black Ajah initiate an attack on Egwene al'Vere in Tel'aran'rhiod. Saerin is told to wake but can't leave due to Perrin Aybara bringing the Dreamspike over Tar Valon. She participates in the Battle in Tel'aran'rhiod.
The Last Battle
Saerin is one of the five that Egwene takes with her to sign the Dragon's Peace. During the meeting, she brings up the point that this document would effectively be null and void if they cannot get the Seanchan Empress to sign it. After the battle is won, she and Elswell Sedai help persuade Rodel Ituralde to become king of Arad Doman. She and three other sitters - Yukiri, Rubinde and Lyrelle Arienwin - persuade Cadsuane Melaidhrin to become the Amyrlin Seat.