It's been thousands of cycles since the sphere of light drove the darkness from Terra. Auron and his remaining Omans understood they could no longer interfere with the natural progression of human life, so they created a structure concealed within the clouds to watch over and protect the life upon their planet. In time, Auron believed the humans could become more powerful than the Omans but knew the darkness would stop at nothing to return Terra to its original desolate state.