Achlys

Achlys was, according to some ancient cosmogonies, the eternal Night (perhaps the Mist of Death, which fell before the eyes preceding death), and the first created beings which existed even before Chaos.

According to Hesiod, she was the personification of misery and sadness, and as such she was represented on the shield of Heracles: pale, emaciated, and weeping, with chattering teeth, swollen knees, long nails on her fingers, bloody cheeks, and her shoulders thickly covered with dust.

If she was a daughter of Nyx, then she may have been numbered amongst the Keres.