Commissionaire Sergeants are denizens in the troops of Monday's Noon, who protect the Lower House.
Unlike Metal Commissionaires, Commissionaire Sergeants are Deinzens who have been appointed to this task rather than being created to do so in the Far Reaches by Grim Tuesday. They stand higher than the Metal Commissionaires and wield sabres flickering with internal light. It is mentioned that they have higer intellegence than the Metal Comissionaires, undoubted due to the fact they were made by the Architect as denizens as opposed to being made by Grim Tuesday.
Whether beong granted the post of Commissionaire Sergeant is a demotion or promotion for deniznes is unmentioned.