Chief engineer and executive officer of the Rocinante. A Belter of exceptional intelligence and technical skill who carries a painful past involving the Free Navy. The moral conscience of the crew, she is also one of the most capable engineers in the solar system.

Mechanic and general muscle aboard the Rocinante. A man who grew up in the worst conditions Baltimore had to offer and emerged without the capacity for moral judgment most people take for granted - he outsources that function to people he trusts. Straightforwardly violent when necessary, and deeply loyal to those he considers his people.

Pilot of the Rocinante and former MCRN officer. A Martian with a warm, garrulous personality that masks genuine melancholy about his failed family life. One of the finest pilots in human space, with an instinctive feel for orbital mechanics and ship handling.

Martian marine gunnery sergeant who witnesses something on Ganymede that her government wants buried. One of the most physically formidable characters in the series, she is also one of its most principled - a soldier who cannot stop asking whether the orders she follows are worth following.

Daughter of the magnate Jules-Pierre Mao, who frames Holden for a terrorist attack in a misguided attempt to restore her family's honour. After her imprisonment she joins the Rocinante crew, carrying significant guilt and a body modified for violence she is trying to leave behind.