[Baalz]

"In Babylonian myths, Tiamat is a huge, bloated female dragon that personifies the saltwater ocean, the water of Chaos. She is also the primordial mother of all that exists, including the gods themselves. Her consort is Apsu, the personification of the freshwater abyss that lies beneath the Earth. From their union, saltwater with freshwater, the first pair of gods were born. They are Lachmu and Lachamu, parents of Ansar and Kisar, grandparents of Anu and Ea.

In the creation epic Enuma elish, written around 2000 BCE, their descendants started to irritate Tiamat and Apsu so they decided to kill their offspring. Ea discovered their plans and he managed to kill Apsu while the latter was asleep. Tiamat flew into a rage when she learned about Apsu's death and wanted to avenge her husband. She created an army of monstrous creatures, which was to be led by her new consort Kingu, who is also her son. Eventually, Tiamat was defeated by the young god Marduk, who was born in the deep freshwater sea. "

I was thinking along the lines of wrathful seas that Tiamat is the logical angle to extend MA Oceana thematically, being the goddess of chaos and saltwater and already referenced in the game. Probably too powerful to be directly summoned, but she's also famous for creating a hoard of monsters.

"Meanwhile, Tiamat created monster serpents as her invincible weapons. She filled their bodies with venom instead of blood and gave them sharp teeth and long fangs. She fashioned terrifying dragons and crowned them with halos like the gods, so that anyone who looked upon them would perish from fright. Once the serpents stood upright, no one would be able to stand against them. She created eleven monsters in all: the viper, the dragon, the sphinx, the great lion, the mad dog, the scorpion-man, three might storm demons, the dragonfly, and the centaur."