Marduk
Marduk is a third-generation god in the Enuma Elish, the son of Ea who is the son of Tiamat and Abzu. Abzu and Tiamat are disputing, because Abzu wants to kill the gods who have been born within the body of his wife, Tiamat. Marduk is similar to Zeus from Greek mythology, because they're both third-generation gods, and they both rise to power by slaying their ancestral deities.
For Marduk, this meant conquering Tiamat and her legion of titanic serpents. In the end of the conflict, Marduk slays Tiamat by ripping her in half, which constitutes the creation of the waters of the earth and the sky (and by proxy, also the atmosphere between them). He then subjects her serpents to service on the earth as natural forces.
Abzu
Abzu is the patron god who fathers the second-generation gods, Ea and his brothers, with his wife Tiamat. Abzu is the fresh waters and Tiamat is the oceanic waters. When they conceived new life, they were annoyed, because the new gods were rowdy and disturbed the peace of their parents. This led Abzu to want to murder the new gods to restore his peace, but Tiamat loved her children and didn't want them to die.
Tiamat
Tiamat is the matron goddess, the mother of the gods. Her defeat by her grandson, Marduk, is a tragedy, because it was her own actions that incurred her destruction. She warned Ea of Abzu's plan to kill them, which prompted the revolt that took Abzu's life. In the wake of her husband's death, Tiamat remarries to Kingu and raises a legion of primordial beings, mostly serpents, to raise her new husband to the throne where Abzu had been. But she lost, and Marduk slayed her.
Mummu
Mummu is an advisor to Abzu's throne. It was Mummu who helped Abzu decide to kill the gods, against the will of Tiamat.
Ea
Ea is the father of Marduk, who created the world. Ea and his brothers were the loud children who annoyed their parents enough to provoke a war of the gods. Ea is warned by Tiamat of the eminent attack and allows a chance for the children to overthrow their murderous father.
