| M. Didius Falco | a principled informer (who needs the money) |
| Helena Justina | the guardian of his ethics |
| Julia Junilla and Sosia Favonia | their children (never ill; never naughty; never loud) |
| Albia | a British visitor, who has seen nothing yet |
| Nux | a dog, who owns Falco |
| The Sacred Geese of Juno and the Augurs’ Sacred Chickens | religious poultry’s free-range omelet producers |
| Ma | a mother shamed by impiety |
| Verontius | Falco’s brother-in-law, as straight as a Roman road |
| D. Camillus Verus | Helena’s father, a senator with memories |
| Julia Justa | her mother, a matron with connections |
| A. Camillus Aelianus and Q. Camillus Justinus | Falco’s Associates, on a long learning curve |
| Ursulina Prisca | a valued client; very litigious |
| L. Petronius Longus | Falco’s friend in the vigiles, a useful contact |
| Anacrites | Falco’s enemy, a useless spook |
| Glaucus | Falco’s trainer, who has seen it all |
| Ti Catius Silius Italicus | a high-class lawyer (with a dubious past) |
| C. Paccius Africanus | a trusts expert (with a shady reputation) |
| Honorius | a legal idealist (heading for disillusion?) |
| Marponius | a judge with encyclopedic knowledge |
| Bratta | an informer’s informer |
| Procreus | an accuser’s accuser |
| Euphanes | a sickly herbalist |
| Rhoemetalces | an apothecary who takes his own medicine |
| Claudius Tiasus | a funeral director with a chipped nymph |
| Biltis | a professional mourner, taking an interest |
| Spindex | a funeral clown; not laughing much |
| Olympia | a fortune-teller; therapist to the nobility |
| Scorpus | aka “Old Fungibles”; a wills expert |
| Scythax | the vigiles doctor, prescribing caution |
| Aufustius | a banker with profligate clients |
| Euboule | a wet nurse who fosters doubts |
| Zeuko | her daughter, keeping it in the family |
| Perseus | a door porter who knows too much |
| Celadus | a steward who knows what the last meal was |
| Julius Alexander | a loyal land agent who knows where the loot is |