The Infernals were the ruling demons of Infernus until their subordinates, the Chthonians, rose up and rebelled. These are said to have eaten the Infernals under the leadership of Hostilius.
Many Infernals were killed, although a significant number managed to escape and avoid detection. A group of these Infernal demons, led by Kal'Ger the Warmonger, would reorganize themselves into the Kal'Gerion. There are also smaller groups of Infernal demons that are not affiliated with this group. The Mahjarrat Bilrach was interested in allying with the Infernal demons and eventually managed to find the Kal'Gerion on an unknown plane.
Like many of their lesser brethren, Infernal demons are capable of creating demonic pacts, although such pacts are considered to be extremely rare and valuable, due to the lack of Infernal demons that were active on Gielinor during the Gielinorian God Wars. Dagon the Gatekeeper, one of the few Infernals known by name, was tricked into forming a pact with the Order of Dis during the early Third Age. Where he was before is unknown. Dagon also claims that Infernals are demons of their word.
The true form and nature of the Infernals remains a mystery, as the only ones encountered so far are actually possessing the bodies of Avernic demons. This Avernic "shell" which the Infernals inhabit is considered deeply uncomfortable, but they appear unable to rid themselves of it for the time being.
- ^ Palkeera, "Palkeera's memory", RuneScape. "The earliest race - at least, that I know of - were the Infernals, and though I do not think they were the original rulers of their planet, they were at their height the undisputed masters of the demon races. Thousands of years ago, the Chthonian race rose up, overthrew the Infernals, and took their place as overlords"
- ^ Dagon the Gatekeeper, "Infernal Source", RuneScape. "What? No! Infernals are demons of their word."
- ^ Umbral Diplomacy#Demonic thoughts, written by Yor'Ger the Deceiver, RuneScape. "This is humiliating. To be brought to this, to be bargaining with these disgusting, fallen things. My Avernic shell itches and crawls, and a fire burns deep in its belly. I long to be rid of it, but I must endure."