Many creation myths begin with a division, and proceed to cut the world ever more. In the garden of Eden all exists within paradise until the idea of Good and Evil is accepted by the community. Later, hierarchy is introduced when Abel is raised above Cain.
Cain becomes rejected from the community after lashing out. He is labeled Evil, and Unworthy, and offered no reconciliation. The fallout from this event echoes through our timeline, and ends with monsters rising from the sea, total chaos.