Epiales

In Greek mythology, Epiales (Ἠπιάλης) was the spirit (daemon) and personification of nightmares. Alternate spellings of the name were Epialos (Ἠπίαλος), Epioles (Ἠπιόλης), Epialtes (Ἐπιάλτης) or Ephialtes (Ἐφιάλτης).

Family
Epiales was probably numbered amongst the Oneiroi (Dream-Spirits) and thus one of the sons of the goddess Nyx (Night).

Mythology
Epiales was also known as Melas Oneiros (Black Dream). "The words epialos, epiales and epioles denote (1) the feverish chill (2) the daimon who assaults sleepers. Homer and most writers have epioles with the e; the form in -os means something different, namely the feverish chill . . . Alkaios (Alcaeus) called it epialos. Apollonios says that Epialtes itself (the nighmare daimon) is called Epiales and by a change of a to o Epioles."

"[The goddess Gaia (Earth) is invoked to drive away a nightmare :] Like a spider, he [a rapist] is carrying me [a woman] seaward step by step--a nightmare (oneiros), a black nightmare (melas oneiros)! Oh! Oh! Mother Earth (Ma Ge), mother Earth (Ma Ge), avert his fearful cries! O father Zeus, son of Ge (Earth)!"

In popular culture

 * Epiales appears as an antagonist in the novel The Sun and the Star where Epiales is depicted as the demon of nightmares and the child of the primordial goddess of darkness Nyx. Epiales traps Nico di Angelo and Will Solace in their worst nightmares before Will's powers of light allow him to overcome the demon. Before Will kills them, Epiales reveals that their mother had sent them after the two demigods. A reformed Epiales later appears alongside their siblings Nemesis and Hypnos to help Nyx out, but turns against their mother with their siblings, citing that the demigods actually appreciate the demon's talents, and restraining Nyx long enough for them to escape.