According to
Joan Goodnick Westenholz, Ishum's mother was Sudaĝ, one of the names of the wife of Shamash (
Aya). Due to an association between Sudaĝ and Sud (
Ninlil), a myth lists the latter as his mother instead. Manfred Krebernik considers this to be the result of confusion between the names, rather than syncretism. Ishum's father was Shamash. After the Old Babylonian period, Ishum came to be seen as the
sukkal (attendant deity) of Nergal, replacing
Ugur. The god list
An = Anum is the only source which explicitly refers to Ishum as Nergal's sukkal, but his activity in literary texts is often related to this function. He often appears in enumerations of deities of the underworld, for example in
Šurpu (alongside Nergal,
Shubula and
Šar-ṣarbati) and on a
kudurru (boundary stone) of
Marduk-apla-iddina I, the "
land grant to Munnabittu kudurru" (alongside Nergal, his wife Laṣ, Shubula and the pair
Lugal-irra and Meslamta-ea). Shubula appears alongside him particularly commonly in known sources, but the nature of the connection between them is not certain. While it is commonly assumed that Shubula was Nergal's son, Jeremiah Peterson remarks that in the light of recent research it is possible that he was Ishum's son instead. In one text, Ishum and Shubula are called the "gods of
Tigris and
Euphrates." When first introduced to the Mesopotamian pantheon, Ishum was not conflated with any Sumerian god of analogous character, similar to other minor gods of Akkadian origin, such as
Shullat and Hanish. Starting in the Old Babylonian period, he came to be equated with
Hendursaga in bilingual contexts, with the former appearing in Akkadian and the latter in Sumerian formulas. They were also equated with each other in the Weidner and
Nippur god lists, and possibly in
An = Anum, though due to state of preservation and possible scribal errors the last case is uncertain. However, the reasons behind the association between these two gods are presently unknown. Another god closely related to both of them was Engidudu, who was the divine guardian of the Tabira Gate in the city of
Assur. In the
Epic of Erra, Engidudu is used as an alternate name of Ishum. In a bilingual Akkadian-
Amorite lexical list dated to the Old Babylonian period, Ishum s Amorite counterpart is a deity whose name is not fully preserved, a-a-[x]-um. While full reconstruction is not possible,
Andrew R. George and suggest that the most plausible interpretation is that the name is a derivative of the
root ʔwr, "to shine", and thus a cognate of Akkadian
urrum, "dawn, daytime",
Ugaritic ảr, "light", and
Hebrew ʔōr, "to shine" and
ʔōr, "light". On this basis they suggest the restoration
a-a-[ru]-⸢um⸣, pronounced as /ʔārum/. Presumably this figure was a minor god in the
Amorite pantheon. Ishum's wife was
Ninmug, a goddess of crafts and birth originally worshiped in Kisiga. They are first attested as a couple in the Old Babylonian period. As in the case of other divine wives, such as Aya and
Shala, Ninmug was invoked to intercede with her husband on behalf of worshipers. No children of this couple are known. Ninmug could also be regarded as the wife of Hendursaga, but this was a secondary development based on the equation between him and Ishum. It is possible that in the third millennium BCE, Hendursaga's wife was instead
Dumuziabzu, the tutelary goddess of
Kinunir (Kinirsha), a city in the state of
Lagash, though in that period family relations between deities were often particularly fluid or uncertain. ==Mythology==