Infernus, also known as Pandemonium, or the Infernal Dimensions, due to the fact that the plane consists of multiple planes stacked on top of each other  is described as a world devoid of any life and contains liquid fire and rocks, somewhat akin to the Mahjarrat homeworld of Freneskae.
Infernus has had a tumultuous history, with power often changing hands. The earliest known race and master of Infernus are the aptly named Infernals, however after a length of time as 'undisputed masters' of this world, they were otherthrown by a subordinate race of demons, known as the Chthonians.
These Chthonians were led by a particularly corpulent thing known as Hostilius the Autocrat, who became the leader of Infernus after the Chthonian rebellion took place. It was during Hostilius' reign that Zaros arrived, attempting to barter with Hostilius. He offered the Chthonians the secrets of travelling between worlds to devour whole new races - in return for twelve legions of demons. Hostilius drew up a Magically Binding Contract to seal the deal, but in the fine legalese of the document included a clause that stated the loyalty of these twelve legions would remain with the eldest of the signatories, who Hostilius believed to be himself. Zaros noticed the clause when reviewing the contract - but allowed it to go through. Hostilius barked with triumph - however, Zaros revealed to the assembled demons of his own origins; aeons ago, in a time that predated their race. The humbled Hostilius pledged to Zaros his twelve mightiest dukes and their legions. Little did he know that in doing so he had unwittingly sown the seeds of his own eventual downfall.
Living amongst the comparably weak humans of Gielinor was somewhat of a luxury, as in their eyes even the lowly Avernic were mighty beings amongst the elite of society. These Avernic started to develop rebellious ideas, unbeknownst to their distant Chthonian masters. The Mahjarrat Zamorak used this to sway many of the Avernic to his side - though only two demons pledged outright allegiance, both members of the Tsutsaroth subspecies. When Zamorak defeated his master Zaros, he returned to Infernus and helped the Avernic triumph over their tyrannical Chthonian masters - a task that took him nineteen years. By the time he was done, all Chthonian demons were either destroyed, or exiled to the Abyss.
During the quest The Golem, players travel to a realm where the Elder-Demon Thammaron once resided, and where he eventually launched a final assault on the city of Uzer in the Kharidian Desert in what would be later referred to as the Battle of Uzer, an important conflict in the God Wars, during the Kharidian Desert Campaign by Zamorak. The small space, which appears to be Thammaron's throne room, may have been part of an abandoned fortress in one of the Infernal Dimensions.
According to information gathered by Relenor, the largest city on Pandemonium is called Dis, which is ruled by a Tsutsaroth called Gree'gar. He also claims that a giant ball of flame can be found in centre of Pandemonium, from which all demons originate.
- Demon Lords such as Thammaron, Agrith Naar and Delrith.
- Blazehounds are said to come from the Infernal Dimensions, where they guard the Scorched Keep.
- Three subspecies of demons exist upon Infernus- the cannibalistic Chthonians, the Infernals, and the warlike Avernic.
- Alathazdrar is known to have originated from Infernus.
- Infernus is the name given to hell by Dante Alighieri in his famous poem Divine Comedy.
- The name 'Chthonian' may have been derived from the word 'Chthonic', which describes something pertaining to the underworld.
- The name 'Avernic' may have been derived from the classical idea of Lake Avernus - a poisonous lake said to be connected to Infernal Realms.
- The player can see Infernus through the World Gate, describing it as a 'Many twisted planes filled with fire'.
- Anya (a possible personality given to an item with the Talking perk) claims to be from Infernus, also stating that she was the 'HDBIC'.
- ^ Jagex. Mod Stu's Twitter account. December 12, 2017. Mod Stu: "Bear in mind that there's also coterminous planes, incorporeal planes, multi-dimensional planes like the shadow realm. Infernus consists of multiple planes stacked on top of each other, for example. Also, there can be and usually are multiple worlds on the same plane."
- ^ a b Palkeera, Palkeera's memory, RuneScape.
- ^ a b Sliske, Sliske's memory, RuneScape.
- ^ Zemouregal, "Zemouregal's memory", RuneScape.
- ^ Mod Mike. "Skypouncer vs. Blazehound." 17 December 2012. General Forums.
- ^ Alathazdrar, RuneScape. "For millennia I have served and waited on the mighty Demon Lords of the Infernal Dimensions."
|Realms and worlds|