There is a precedent for such racial prejudice. Jenny Strauss Clay observed “Gaia, whose lineage remains completely separate from that of Chaos – intercourse between these two fundamentally opposite cosmic entities seems impossible”. The Fates decreed that some specific members of these clans could not meet. (Please see TFBT: The Divine Aversion to Death and Nyctophobia
In the beginning Earth, Gaia, produced the primordial god of the sea, Pontus. Their children were the ancient sea gods of the Aegean and Mediterranean, among them Nereus and the great sea-monsters that frolicked there. These are the Pontides. Next, she produced Uranus, the starry sky. Their children would include Cronus, future king of the gods and Oceanus, the personification of the great fresh-water river that encircled the world. These are the Titans. The Titans in turn were parents of the second-generation Titans including those latter called Olympians.
To Bed a Sea Monster