He was regarded either as a son of Ereshkigal and a "Great Lord" (possibly to be identified with Gugalanna, known from the god list An = Anum and from the myth Inanna's Descent to the Nether World), who might have been analogous to anonymous deities described as "mighty cow" and "untamable bull" attested as his parents elsewhere, of Enlil and Ninlil (an association originating in Eshnunna but present also in other sources, including the myth Enlil and Ninlil), or of Suen.
[10] Frans Wiggermann assumes that the genealogies where Ereshkigal is listed as his mother represent the original tradition, and making Ninazu a son of Enlil and Ninlil was the result of absorption of some features of Nergal.
[7] The children of Ninazu and Ningirida were the god Ningishzida and his two sisters, in a single incantation he is also addressed as the father of the healing goddess Nintinugga.
"[20] Frans Wiggermann notes that the hymn presents an "aberrant," otherwise unknown, genealogy of Ninazu, calling him "offspring of Mami," which according to him might entirely depend on implicit identification with Ninurta in this context.
[26] Much like Ninazu himself, Enegi was associated with the underworld, and could be described as "pipe of Ereshkigal's quay" in literary texts in reference to a type of implement used in funerary libations.
[27] The cults of Enegi were likely influenced by Uruk, as in addition to Ninazu, typical Urukean deities like the messenger goddess Ninshubur, the demigod Gilgamesh and his mother Ninsun were venerated in this city.
[28] Starting in the Akkadian period, Ninazu apparently competed with the god Tishpak in Eshnunna, and ceased to be mentioned in documents from it altogether after Hammurabi's conquest.
[28] While similar in character, Ninazu and Tishpak were not fully conflated, and unlike Inanna and Ishtar or Enki and Ea were kept apart in god lists.
[12][29] In Lagash, Ninazu was one of the deities who were part of the official pantheon during the reign of Urukagina,[30] but he is otherwise not attested there in the Early Dynastic period,[31] with the exception of some theophoric personal names.
[12] A temple dedicated to him in this city was also named Egidda,[30] and it has been proposed that it might have been where the center of his cult was relocated after the decline of Enegi suggested by its absence from records from the first millennium BCE.
[36] The last available evidence for cult of Ninazu are theophoric personal names from Ur invoking him, present in sources from the period of Persian rule over Mesopotamia.
[38] It is possible that this situation was influenced by the role played by lamentation priests, who traditionally memorized texts written in the Emesal dialect, in the survival of Ninazu's cult.
[39] Other underworld deities, like his son Ningishzida, the deified snake Nirah and the incantation goddess Ningirima, also retained a degree of popularity, likely due to being envisioned as members of Ninazu's court.