Cethegus was a Jiralhanae Chieftain in the Covenant military during the final years of the Human-Covenant war. He was with Truth's fleet when the Prophet of Truth travelled to Installation 00 and was killed during the battle by John-117.
Cethegus was part of the Covenant military, having worked his way up the ranks of his pack. He demonstrate considerable martial prowess against Kig-Yar mercenaries, UNSC forces and Sangheili warriors. By the early 2540s, Cethegus had become Chieftain of his pack and had garnered considerable fame in the eyes of both his fellow Jiralhanae and the High Prophets for exploits during the war. In 2552, Cethegus and his pack arrived on Earth as part of Truth's fleet, fighting humanity on its homeworld. When Truth led the Covenant through the Portal at Voi, Cethegus was with him. Cethegus and his pack were among some of the first Covenant forces deployed to the surface of Installation 00 upon emerging from the Portal, seizing and defending the Ark's Cartographer from the combined assault of the UNSC and the Swords of Sanghelios. It was here that Cethegus was given a direct order from Truth: to slay John-117 before he could stop the activation of the Halo Array. Seeking to earn Truth's favor and receive the title of Chieftain of the Jiralhanae, Cethegus engaged the SPARTAN in a duel. Both Cethegus and his pack would be slain at the hands of the SPARTAN.
Cethegus's pack consisted of an assortment of standard Jiralhanae infantry, ranging from Minors up to Captain Ultras. Cethegus also commanded two special operations elements: a team of flight-fighters and a team of stalkers.