Khreus

Khreus, the Ever-Changeful, the Mother of Oceans, was one of the Aiyu-Atma. She was the primordial goddess of the sea and the sister of Nysseia and Epheos. When creation was still young, it was she who filled unformed Urva with the primeval waters which were her essence, from which Kordan then raised up the stones and mountains to form dry land. Khreus was destroyed by vile Ymuz in the wars of the Old Gods before mortal races were born; legend tells that Aurhion then wrought the moon as her funeral vessel and set it in the sky to soften the grief of Nysseia for her beloved sister. Even today the tides of the sea align with the rising and setting of the moon, and with its phase; the waters of the ocean still yearn for lost Khreus who was their source and mother. 
The three daughters of Khreus are the triple sea-goddesses Sherian, Shenoa, and Nyra, collectively known as the Khreianoa. Myth and tradition have it that since the destruction of Khreus in the ancient age, the seas of Urva have been divided between the inconstant and ever-shifting dominion of these three daughters.