| Caleb | Calhoun | American. Proprietor of The Singing Sparrow. |
| María | de Santibáñez | Beast's mother. |
| Eddie | Doolan | One of the thugs in the Covent Garden market. |
| Michael | Doolan | One of the thugs in the Covent Garden market. aka Mikey. |
| | Eversley | Marchioness. Attended the Duchess of Warnick's Ball. |
| Eleanora | Madewell | Hattie's best friend. Duke's daughter. aka Nora. |
| Elisabeth | Madewell | Duchess of Holymoor. Nora's mother. Deceased. |
| Peter | O'Malley | One of the opponents of Beast. |
| Sally | Sasser | Acquaintance of Beast when he was younger. |
| Andrew | Sedley | Earl of Cheadle. Hattie's father. Owner of Sedley Shipping. |
| August | Sedley | Hattie's younger brother. aka Augie. |
| Henrietta | Sedley | Protagonist. aka Hattie. |
| Sesily | Talbot | Acquaintance of Caleb. |
| | Warnick | Duchess. |
| | Warnick | Duke. |
| Saviour | Whittington | Protagonist. aka Whit. aka Beast. |
| Abraham | | Works for Beast and Devil. |
| Annika | | Works for Beast and Devil. Second in command. aka Nik. |
| Bess | | Young girl selling flowers in the Covent Garden market. |
| Brixton | | One of the best runners of Beast and Devil. |
| Clare | | Isla's twin. |
| Dahlia | | Owner of 72 Shelton Street establishment. |
| David | | Works for Beast and Devil. |
| Devil | | Beast's brother. One of the Bare knuckle Bastards. |
| Dinuka | | Beast's 2nd outrider. |
| Felicity | | Devil's wife. |
| Isla | | Miles' daughter. |
| Jamie | | Young man working for Beast and Devil. |
| Marco | | Works for Beast and Devil. |
| Mark | | Works for Beast and Devil. |
| Mary | | Doctor's wife. |
| Miles | | Works at Sedley Shipping. |
| Niall | | Works for Beast and Devil. |
| Rebecca | | Selling puppies at Covent Garden market. |
| Robert | | Duke of Marwick. aka Ewan. |
| Robert | | Works for Beast and Devil. |
| Russel | | Augie's valet and friend. |
| Sarita | | Works for Beast and Devil. |
| Seth | | Rebecca's husband. |
| Zeva | | One of Dahlia's employees. |
