Cthulhu is a malevolent entity who hibernates somewhere beneath the ocean in the South Pacific. The imprisoned Cthulhu is the source of constant anxiety for mankind at a subconscious level, and also the subject of worship by a number of human religions.
Nyx, goddess of the Night. Nyx stood at or near the beginning of creation, and was the mother of personified gods such as Hypnos (sleep) and Thánatos (death). She is found in the shadows of the world and only ever seen in glimpses.