The Rhoynar religion spread to Westeros with the migration of the Rhoynar, and the orphans of the Greenblood in Dorne continued to preserve this faith in the Rhoyne.
After Nymeria led the Rhoynar across the Narrow Sea, landed in Dorne, and married Mors Martell, their religious beliefs also became woven into Dornish culture.
The Rhoynar religion lacked the rigorous organizational structure and systematic theology of the Faith of the Seven. Its religious practices took the form of local rituals and legends passed down by word of mouth.
The stories of the Crab King and the Old Man of the River were preserved through generations of oral tradition, becoming an important part of the Rhoynar cultural heritage. These legends held not only religious significance but also the historical memories and moral teachings of the Rhoynar people, making them an important means of understanding Rhoynar civilization.
In Rhoynar mythology, the Crab King was a distinctive lesser water god whose image and legends were deeply rooted in the natural environment and cultural traditions of the Rhoyne basin.
As an important deity beneath Mother Rhoyne, the Crab King was usually described as a gigantic crustacean, combining the features of a crab with human intelligence. He could command all underwater creatures and, at certain times, profoundly influence the ecology and human life of the Rhoyne basin.
The Crab King's place in mythology reflected the Rhoynar's reverence for aquatic creatures and their dependence on them. In daily Rhoynar life, crabs and other aquatic creatures were not only important sources of food but also indicators of the ecosystem's health.
Deifying the crab as the "Crab King" reflected the Rhoynar's early attempts to understand natural phenomena through personification.
The image of the Crab King might have originated in the abundance of large crabs in the Rhoyne delta or