War criminal

A war criminal is a person who violates the laws of war during a conflict and commits various heinous acts. Examples of war crimes can include torture and genocide. During the Human-Covenant War, a number of war crimes were committed, particularly by the Covenant who sought the genocide of the human race. After an encounter with Prelate Tem'Bhetek, Sangheili Supreme Commander Rtas 'Vadum decided to track down the remaining San'Shyuum and determine which deserved to be punished for war crimes during the Great Schism and which ones had committed no crimes and were merely misled.

Notable examples of war criminals

 * High Prophet of Truth - Orchestrated and led the genocide of humanity. Orchestrated the Great Schism. Attempted to fire the Halo Array and commit galaxy-wide genocide. Executed by Thel 'Vadam after being defeated during the Battle of Installation 00.
 * High Prophet of Mercy - Orchestrated and led the genocide of humanity. Died after a Flood infection form was removed from his neck by John-117 during the Fall of High Charity.
 * High Prophet of Regret - Orchestrated and led the genocide of humanity. Personally commanded the glassing of Charybdis IX. Attempted to have Arbiter Ripa 'Moramee use a fleet of Forerunner s to destroy the human race "quickly and with ease." Personally led an attack on Earth,  and attempted to fire the Halo Array to commit galaxy-wide genocide. Assassinated by John-117 during the Battle of Installation 05.
 * Tartarus - A driving force in the genocide of humanity, he personally led the destruction of the planet Harvest and as the Chieftain of the Jiralhanae, led his race in an effort to eliminate the Sangheili during the Great Schism. Attempted to commit galaxy-wide genocide by activating the Halo Array, but was defeated and killed during the Battle of Installation 05 by the combined forces of Sergeant Avery Johnson and Arbiter Thel 'Vadam.
 * Thel 'Vadam - As part of the Covenant, took part in the glassing of several planets including Madrigal, Charybdis IX and Reach and the extermination of their inhabitants. Pardoned by the UNSC after aiding John-117 at the end of the war. Became a valuable ally during Created conflict for the UNSC.
 * Ur-Didact - Attempted the genocide of the human race at Earth with the Composer before being foiled by John-117 and Cortana. Succeeded in killing seven million people in New Phoenix. Digitized following the Mission to Installation 03 by Blue Team.
 * Doctor Catherine Halsey - Considered a war criminal by many in the UNSC for "committing acts likely to aid the enemy" by stealing the Beatrice, kidnapping Kelly-087 and telling Lord Hood to send more Spartans to Onyx — all with the sole intention of hiding in the shield world until the war was over, crimes for which she was arrested and imprisoned upon emerging from the shield world in 2553. Later gave direct aid to Jul 'Mdama and his Covenant. Currently aiding the UNSC in effort to thwart Cortana's ambition and Created on Created conflict.
 * SPARTAN-II Gray Team - Destroyed the Sangheili colony world of Glyke with a NOVA bomb days just after a tentative peace treaty was established with the Swords of Sanghelios, killing billions. In 2558, following the Battle of Carrow, was offered a deal by ONI where in exchange for their joining an interspecies strike force operating in the Joint Occupation Zone, they would receive a formal pardon from Thel 'Vadam. After adding a list of their own demands, Gray Team accepted the deal and were pardoned for their actions.

List of appearances

 * Halo 2
 * Halo 3
 * Halo 4
 * Halo: The Fall of Reach
 * Halo: First Strike
 * Halo: Contact Harvest
 * Halo: The Cole Protocol
 * Halo: Glasslands
 * Halo: Shadow of Intent
 * Halo: Envoy