The books are set in a realm similar to ours, but separate. They tell the story of the Hath family, and the Manth people who go on a long, and harsh journey from their city-prison, to their homeland. The main characters, Kestrel and Bowman Hath, are twins that have certain powers that allow them to save their people, and friends, from an evil power called the Morah. The first book tells of the events unfolding near and inside Aramanth, the second one talks about the lives of the Manth people in The Mastery, and the third book concludes with their voyage to the homeland.
In the first book The Wind Singer the protagonists are Kestrel and her beloved empath brother, Bowman. They live in a city called Aramanth controlled by Examiners. In order to be successful, the entire population of the city must undergo Exams every year. Kestrel is a strong-willed individual who fiercely loves her family and despises the Exams. So great is her hatred of them that she scales a tall structure, the Wind Singer, and denounces all the values and principles of Aramanth at the top of her voice, as well as denying the existence of the Emperor, the unseen ruler of Aramanth.
This sets in motion a chain of events that eventually results in Kestrel, her brother, Bowman and a rather disgusting child called Mumpo escaping from the city and going on a quest to save their people from an evil entity known as The Morah which controls an army of malevolent and numberles entity called The Zars, which have one desire, to kill.
The story ends with the city of Aramanth destroyed and the Manth people leaving to find another home.
Kestrel shares a deep emotional bond with her twin brother Bowman which allows them to communicate telepathically.
Bowman Hath: Kestrel's twin brother. He is somewhat empathetic, and can 'read' hearts and minds. As a person, Bowman is much quieter, less outspoken and less rash than his sister. A phrase often used to describe the two is "He is the one who feels, and she is the one who does". Bowman assists Kestrel and Mumpo in the retrieval of the wind singer's voice, is taken as a slave to the Mastery and later helps the Manth people to find their homeland. He also falls in love with the Johdila Sirharasi ("Sisi"), a princess of the land of Gang. Although he at first does not pursue their relationship, believing he had to die in order to defeat the Morah, it turns out that Kestrel must die instead of him. Bowman marries Sisi, becomes the ruler of Gang and has three children: Sirharani, Falcon and Ira.
Maslo Inch: The power-hungry High Examiner of Aramanth in Book 1. He punishes the Hath family for rebelling against his system of examinations and ratings, but is stripped of power when Aramanth is freed from the Morah. He also discovers that he is the father of Mumpo. After the loss of his title, Maslo becomes a humble person, and hardly an adequate father for Mumpo. He is burned to death by Marius Semeon Ortiz, a general of the Mastery.
Pinto (Pinpin) Hath: Kestrel and Bowman's younger sister. She takes her first test at the age of two at the beginning of the story. As she grows older she becomes infatuated with Mumpo, to the point of hating her sister, through jealousy of Mumpo's adoration of her. She shares Kestrel's fiery determination, and can communicate telepathically with wolves. She eventually marries Mumpo.
Hanno Hath: Kestrel, Bowman and Pinto's father. He works as a librarian, and although intelligent, performs poorly in Aramanth's High Examinations due to his quiet rebellion against the system. When he is taken away to a Residential Study Course, which is described as "more like prison", he stirs himself and the other members up in rebellion. Members of this group, including Miko Mimilith and especially Scooch, become more trusting of Hanno through this. Hanno becomes the leader of the Manth people after they escape from the Mastery and successfully leads them to the Manth homeland.
Ira Hath: Hanno's wife. Descended from the great prophet Ira Manth, Ira often enjoys using her 'prophetess voice'. She decides, after Kestrel and Bowman begin their quest and her husband is imprisoned, to actually act as a prophetess, wearing forbidden many-coloured clothing and standing at the foot of the wind singer to preach to the people. Throughout the second and third books, her powers of prophecy grow as her strength wanes. She eventually leads the Manth people to their promised land, but dies just before she herself reaches it.
Mumpo: A dribbling and foul-smelling boy who is at the bottom of Kestrel's class. It is implied that he suffers from some form of learning disability. As the books progress, however, he matures and becomes surprisingly endearing. Kestrel hates him in the first book and is angered that he joins her quest, but learns to like him. In the second book he trains to be a gladiator for the Mastery. This training makes him the Manth people's best warrior.
Sirharasi (Sisi): Featurings only in books 2 and 3, she is a beautiful but spoiled and childish princess, who has an arranged marriage to Ortiz, heir of the Master. After falling in love with Bowman, she rebels and refuses to marry, which throws the whole country of the Mastery into chaos, she then marries Bowman and has several children by him.
Marius Semeon Ortiz: The next in line to the Mastery, a prominent general.
Albard: A.K.A. the Master, a rebellious Singer. In Firesong he teaches Bowman how to use his powers.
The Morah: A satanic character, the Morah is mentioned in the first book as being a "Spirit lord" who grew envious of the Wind-Singer and stole its power. The Manth people greatly fear the Morah and deny its existence, dismissing it as a metaphor for the evil in humanity. As such, whenever the Morah is mentioned someone will say "the Morah comes from within." During the first two books the Morah is described as being a single individual responsible for all the pain and suffering in the world but in the third book it is revealed to be a legion of tormented, half-dead human souls, possibly a reference to the demonic character, "Legion" from The Bible. In the first book Kestrel meets an old woman in the Halls of the Morah who later appears as one of the legion of the Morah in Firesong. When she looks into the old woman's eyes she sees a vast congregation of smaller eyes and hears a voice in her head say "We are The Morah, we are legion".
In Slaves of the Mastery, control is achieved with fear and threats. If one person disobeys, many are killed, to discourage others from doing the same. Also, control via strength of mind features frequently, and is a skill which at the end of the book enables the Manth people to fly to their homeland. This control of oneself symbolises the liberation of the Manth people (and the world).
Likewise, The Morah is eventually revealed to be an army of shambling zombies rather an actual individual.