Ur-Nungal of Uruk was the sixth Sumerian ruler in the First Dynasty of Uruk, he was the father of which person that became the seventh Sumerian ruler in the First Dynasty of Uruk?
Ur-Nungal:  He was the father of Udul-kalama. Udul-kalama: Udul-kalama of Uruk was the seventh Sumerian ruler in the First Dynasty of Uruk (ca. 26th century BC), according to the Sumerian king list.
Udul-kalama of Uruk