Who is Captain Fleery from The City of Ember and what is their importance?

Captain Fleery is the head of the Messengers. She is one of the Believers. Lina trusts Fleery and goes to her with the instructions. She genuinely believes that Captain Fleery will help her figure out what the instructions mean, and what she should do with them. Captain Fleery, however, has her own opinion about being saved and believes the Builders will return to "show us the way."