Arioch is a Hebrew name that means "fierce lion". It originally appears in the Book of Genesis chap. 14 as the name of the "King of Ellasar", part of the confederation of kings who did battle with the kings of Sodom and Gomorrah and with Abraham in the vale of Siddim. Earlier in the 20th century, it was common to identify him with "Eriaku" - an alternative reading of either Rim-Sin or his brother Warad-Sin, who were Elamite rulers over Larsa contemporary with Hammurabi, although this identification has come under attack from scholars in more recent years, and is now largely abandoned, in part due to Nuzu inscriptions referring to a Hurrian king named Ariukki.

Alternatively Ellasar could have been the site referred to as Alashiya, now thought to be near Alassa in Cyprus, where there was a Late Bronze Age pallace, destroyed by the Peoples of the Sea.

The same name later appears in the Book of Daniel as the person appointed by King Nebuchadnezzar to put all the wise men of Babylon to death.

Arioch (Arius) was also a grandson of Semiramis in the classical Ninus legend.

Adaptations by later writers

Arioch was a name for a fictional demon, and also appears as the name of a demon in many grimoires. An Arioch is also named in John Milton's Paradise Lost (vi. 371.) as one of the fallen angels under Satan's command.

Arioch appears in Michael Moorcock's fantasy stories about Elric, Hawkmoon and Corum as the name of the patron chaos lord of Elric and his ancestors. He is also known as the "Knight of Swords" and is one of the 3 major deities of Chaos in Moorcook's books about Corum. The other two deities are the Queen of Swords (Xiombarg) and the King of Swords (Mabelode the Faceless). All three deities used mortal pawns like Elric and Corum in their struggle to defeat the Lords of Law. These books have also spawned various pen & paper Role-playing games such as Chaosium's Stormbringer.