In the beginning this primordial deity encircled the Earth and filled it with optimistic goodness.
However, the salty sea waters of Chaos produced by TIAMAT were very bitter. So APSU merged with TIAMAT and became her consort. The waters blended very nicely — he’d obviously allowed fermentation to cease before adding his extra sugar.
As a result of their union, ANU and EA were born, along with all the other Gods, who rapidly took control and started running things. APSU was not too happy about this, so he declared war on them all but was slain by EA and sent to a watery grave.