One of these myths is the famous story of Ishtar's descent to Irkalla or Aralu, as the lower world was called, and her reception by her sister who presides over it; the other is the story of Nergal's offence against Ereshkigal, his banishment to the kingdom controlled by the goddess and the reconciliation between Nergal and Ereshkigal through the latter's offer to have Nergal share the honours of the rule over Irkalla.
The addition of Nergal represents the harmonizing tendency to unite with Ereshkigal as the queen of the nether-world the god who, in his character as god of war and of pestilence, conveys the living to Irkalla and thus becomes the one who presides over the dead.
In this way Ninib, whose chief seat appears to have been at Shirgulla (Lagash), became the sun-god of the springtime and of the morning, bringing joy and new life to the earth, while Nergal of Kutha was regarded as the sun of the summer solstice and of the noonday heat - the harbinger of suffering and death.
That the figures symbolic of Rakab or Hadad were compounded or amalgamated by the Israelites with those symbolic of Nergal (the lion-god) and Ninib (the eagle-god), is not surprising.
Associated with Marduk was his consort Sarpanit, and grouped around the pair as princes around a throne were the chief deities of the older centres, like Ea and Damkina of Eridu, Nebo and Tashmit of Borsippa, Nergal and Allatu of Kutha, Shamash and A of Sippar, Sin and Ningal of Ur, as well as pairs like Ramman (or Adad) and Shala whose central seat is unknown to us.
At the same time, the possibility of a confusion between Ninib and Nergal must be admitted, and perhaps we are to see the solution of the problem in the recognition of two diverse schools of theological speculation, the one assigning to Ninib the role of the spring-tide solar deity, the other identifying him with the sun of the summer solstice.
Ordinarily the consort of Nergal is Laz.
Besides absorbing the prerogatives of Ea and Bel, Marduk was also imbued with the attributes of other of the great gods, such as Adad, Shamash, Nergal and Ninib, so that, more particularly as we approach the days of the Neo-Babylonian Empire, the impression is created that Marduk was the only real deity recognized, and that the other gods were merely the various forms under which he manifested himself.
Portrayed in hymns and myths as a god of war and pestilence, there can be little doubt that Nergal represents the sun of noontime and of the summer solstice which brings destruction to mankind.
It is a logical consequence that Nergal is pictured also as the deity who presides over the nether-world, and stands at the head of the special pantheon assigned to the government of the dead, who are supposed to be gathered in a large subterranean cave known as Aralu or Irkalla.