Rose Williams is Nathaniel and Rachel's mother, whose work as a civilian spy for British Intelligence introduces mystery and complexity to her character.

The Moth, whose real name is Walter, is a large, shy man who serves as Nathaniel and Rachel's guardian, embodying discretion and security.

Norman Marshall, also known as The Pimlico Darter, is a former boxer and greyhound smuggler who educates Nathaniel in the ways of independence and spontaneity.

Agnes is Nathaniel's first love, a mature and perseverant girl from a working-class family who introduces Nathaniel to love and responsibility.

Sam Malakite is a farmer and confidante of Rose Williams, providing Nathaniel with a sense of stability and security in his later visits.

Marsh Felon is Rose's childhood friend and mentor in British Intelligence, whose involvement in Rose's life is characterized by complexity and secrecy.

Olive Lawrence is a geographer and The Darter’s former girlfriend, who offers Nathaniel guidance and represents a broader, interconnected worldview.

Rachel Williams is Nathaniel's older sister, nearly 16 years old when their parents leave, whose estrangement and differing perspectives emphasize themes of disruption and subjective truth.