A native of San Martin, de Sangro joined State Security and rose to the rank of captain in the ground forces. By 1911 PD, she was assigned as second-in-command to one of StateSec's contingents onboard Secretary of Public Information Cordelia Ransom's personal ship, the battlecruiser PNS Tepes. When her detachment commander was killed by the treecat Nimitz during Honor Harrington's sentencing at DuQuesne Base, Captain de Sangro succeeded him and took charge of Harrington until the latter could be left in Tepes' brig for her transportation to Hades.