The origins of the Ruin and the Cultivator

I'd like to hear your theories on the origins of these two forces. They are both incredibly powerful, and as such unlikely to have come into existence by random chance.

Personally, I think a clue may lie in the 8th, destroyed racial portrait on the ancient ruins. What if, when the Cultivator came into existence/some person gained the power that would cause them to be known as the Cultivator, the Cultivator accidentally fused all the members of said species into the being now known as the Ruin? It'd be a nice parallel to the Cultivator: one incredibly powerful being -> a species vs. a species -> one incredibly powerful being. The trauma of its creation would also explain its destructiveness to a certain degree. It'd also explain the unidentified skeletons, being members of the species that died before the species was combined.