Tiamat

Tiamat is a primordial goddess from Sumerian, Babylonian, Akkadian, and Mesopotamian mythology. She is a creator goddess who is thought to embody the water of the ocean. She is thought to have combined with Apsu, who embodies freshwater, and birthed eleven monstrous creatures. She became incredibly angry at Enki and Marduk for leading the deities who later killed Apsu. She created and then married the god Kingu to fight Marduk. Marduk eventually split her in half, using half of her body to make the vault of heaven, and using her eyes as the water sources for the Tigris and Euphrates rivers.

Citations:

Jordan, Michael. Encyclopedia of Gods: Over 2,500 Deities of the World. United Kingdom, Kyle Cathie, 2005.