The Rokea claim that Dagon contacted Qyrl in her dreams and promised her a way to close the Great Wound if she would make him real. Qyrl dreamt of a huge shape of many arms, a muscular body, and wings that could take it to the Great Wound. The Nightmare took the image for itself and burst forth into being and attacked the Great Wound. While standing in Sea, the waters only reached its waist, while Oversea and Sea struggled against it by raining fire on it. Entire civilizations died out during that titanic struggle, until Sea forced Qyrl to undo what she had done. The Tentacled One imagined the Nightmare without wings, and the entity fell back into the sea. Qyrl also imagined it reduced in form, but not in power. Its seed spread and created the Murdhuacha, who were loyal servants of Qyrl even though they revere the Nightmare.
The mer instead claim that Dagon already existed, as a brother to Vatea. When Vatea created the first life on earth, Dagon wanted to emulate him and traveled to the land. The children of Vatea were frightened and worshipped Dagon as a god, fearing his wrath. Dagon let himself be treated as divine figure and became cruel and corrupt. When Vatea dragged him back into the Sea, he fought back and hurt the Sky in the process, creating the Great Wound. Dagon fell into a deep slumber, from which the Murdhuacha came forth. The Murdhuacha believe that when Dagon awakens, he will sink the continents as a gift to his children.
- , p.23-24
- , p.26, 61-62