Achlys/ˈæklɪs/ (Ancient Greek: Ἀχλύς “mist” or “darkness”) is an ancient Greek goddess who symbolizes the mist of death. According to some ancient cosmogonies, Achlys was the eternal night before Chaos.
According to Hesiod, Achlys 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.
She may also have been the goddess of deadly poisons as presented by Nonnus. According to the Dionysiaca, Hera procured from Achlys treacherous flowers of the field which shed a sleeping charm over the sons of the Nymphs Lamusides (nurses of Dionysus). The goddess then distilled poisoned drugs over their hair and smeared a magical ointment over their faces, changing their human shape into that of the Horned Centaurs.
If Achlys was a daughter of Nyx (Night) then she may have been numbered amongst the Keres.
And beside them the Keres (Deaths) and the Moirai (Fates) on the battlefield] was standing Akhlys (Achlys), dismal and dejected, green and pale, dirty-dry, fallen in on herself with hunger, knee-swollen, and the nails were grown long on her hands, and from her nostrils the drip kept running, and off her cheeks the blood dribbled to the ground, and she stood there, grinning forever, and the dust that had gathered and lay in heaps on her shoulders was muddy with tears.
(Hera spies the nurses of the infant god Dionysos): Hera, who turns her all-seeing eye to every place, saw from on high the everchanging shape of Lyaeus [Dionysos], and knew all. Then she was angry with the guardians of Bromios. She procured from Thessalian Akhlys (Achlys, Death-Mist) treacherous flowers of the field, and shed a sleep of enchantment over their heads; she distilled poisoned drugs over their hair, she smeared a subtle magical ointment over their faces, and changed their earlier human shape. Then they took the form of a creature with long ears, and a horse’s tail sticking out straight from the loins and flogging the flanks of its shaggy-crested owner; from the temples cow’s horns sprouted out, their eyes widened under the horned forehead, the hair ran across their heads in tuft, long white teeth grew out of their jaws, a strange kind of mane grew of itself, covering their necks with rough hair, and ran down from the loins to feet underneath.