Sorcha was the only other female in the Guard. She trained Ember for a short while.
Sorcha is first introduced as the woman who will train Ember. She doesn't however because Barrow keeps his word and takes Ember to train.
Sorcha helps Ember dress like a girl when the Abbot comes to visit, having done this many times before, to not let the Abbot know they have female warriors.
Sorcha trains Ember again after Barrow steps sown claiming Ember a "distraction." Sorcha dies awhile later after being accused of witchcraft due to Bosque Mar and Eira's plan. She is burned at the stake.