Wikipedia
In Greek mythology, Achlys ( Greek language: "mist") 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 being 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 (Night) then she may have been numbered amongst the Keres.
Achlys is a small genus of flowering plants in the barberry family ( Berberidaceae), which it shares with genera such as Berberis and Vancouveria.