Z4 Blue was a male Nasat who served as deputy Presidential Chief of Staff to Esperanza Piñiero during the administration of Federation President Nanietta Bacco.

Z4 Blue (sometimes called "Ziff" to his annoyance) made a passionate case for fellow Nasat C29 Green's appointment to the Federation Council's technology sub-council, in spite of Ashanté Phiri's objections. (TNG novel: Articles of the Federation)