Quartigod son of Gilgamesh (Ninsun-paternal demigod), per the Sumerian King List succession-tradition. Reigned canonically as the second king of Uruk dynasty I after Gilgamesh, with the Tummal Inscription preserving an independent reference to him in the Uruk-Nippur temple-rebuilding sequence. The historical-kernel question for all Sumerian-King-List rulers of this period (c.2900-2350 BCE) remains open — the line preserves either genuine Early-Dynastic-period ruler-succession through the Ur III scribal tradition, or retrojected legitimating-genealogy. Either reading places Ur-Nungal in the demigod-to-quartigod dynastic-divinity-dilution position structurally analogous to the Heraclidae sequence in Greek tradition.