The Alyaroth are one of the three named tribes of Avernic demons. They, like all demons found on Gielinor, originated from the fiery world of Infernus, also known as the Infernal Dimensions or Pandemonium.
The Avernic demons were primitive and tribal by the standards of Infernus. They were a slave race, ruled first by the Infernals, and then by the Chthonians that overthrew them. Due to an unspecified 'unique quirk', the Chthonians were unable to feed on the Avernic as they did each other.
Alyaroth are described as being smaller than the Tsutsaroth tribe, which ruled the Avernic demons in a brutal manner, and possessing wings. In Gielinor, the Alyaroth come in several forms, most commonly as greater demons and black demons, but also as jungle demons.