Empire of the devil, territory dominated by the devil. Hell, orc, báratro, abyss, underworld, paila mocha.
In mythology is the place where the souls of the dead go, which is underground and that is why some religions associated it with hell. As it is a dark and dark place, there are no birds singing, and the Greeks called it 945; 959; 961; 957; 953; 962; ( a ornis "without birds") that the Romans interpreted as ab ornis and hence the noun Avernus.
averno: Underworld, space limited to creatures that live under the ground. Caverns. Sewer system. Underground labyrinth where the infra-world lives. Legion of horrific and ruthless creatures that emerge from the underground darkness. Hell.