Yormus was a Jiralhanae Chieftain and arch-nemesis to Stel 'Vadam. He appears in Halo: Journey of a Sangheili, Halo: Sangheili Brothers and Halo: Obsidian Conflict as the main antagonist, and Halo: Desolation as a supporting antagonist. He is briefly mentioned in Halo: The Destined Ones.