Ishum is a minor god in Akkadian mythology, the brother of Shamash

Shamash

Shamash was a native Mesopotamian deity and the sun god in the Akkadian, Assyrian and Babylonian pantheons. Shamash was the god of justice in Babylonia and Assyria, corresponding to Sumerian Utu...

 and an attendant of Erra

Erra

Erra is an Akkadian plague god known from the Erra epos of the eighth century BCE. Erra is the god of mayhem and pestilence that is responsible for periods of political confusion...

. He may have been a god of fire and, according to texts, led the gods in war as a herald but was nonetheless generally regarded as benevolent. Ishum is known particularly from the Babylonian legend of Erra and Ishum. He developed from the Sumerian figure of Endursaga

Endursaga

Endursaga is the herald god in the Sumerian mythology. He leads the pantheon, particularly in times of conflict. In Akkadian times he becomes Ishum....

.