Final answer:
Marduk, the son of the Babylonian god Ea, is the deity who killed Tiamat as recounted in the Enuma Elish, establishing order from chaos.
Step-by-step explanation:
The son of the Babylonian god Ea who killed Tiamat is Marduk. In ancient Mesopotamian mythology, Marduk is a prominent deity associated with creation and order. The legend of Marduk's battle against Tiamat is central to the Babylonian epic, the Enuma Elish. In this narrative, Marduk is granted authority by the other gods to confront the chaotic sea goddess Tiamat, who threatens creation. He defeats her, using her divided body to form the heavens and the earth, thereby establishing order in the universe. The story of Marduk and Tiamat reflects ancient themes of conflict between order and chaos, light and darkness, and serves as a mythological precursor to similar tales in later cultures.