Operation: GREY VEIL

The Office of Naval Intelligence oversaw an assassination mission on the planet Heian circa 2541. . The operation saw death of a Covenant Prophet, as well as the discovery of a series of prehistoric ruins that were of particular scientific interest.

Prelude
Heian was the site of an important Covenant logistics base from which supplies were delivered to the rest of the planets in the system, as well as the entire sector. The UNSC's Office of Naval Intelligence had discovered that a Covenant Prophet was on the planet, and that his death would compromise Covenant logistics operations in the sector, giving the UNSC a strategic advantage. In addition, the planet possessed a series of ruins that predated both the Covenant and the UNSC. In addition to killing the Prophet, the assault team had the secondary objective of documenting these ruins.

A team of four Orbital Drop Shock Troopers led by Master Sergeant Cortez was ordered to carry out the mission. However, the assassination was to be carried out by Spartan Cal-141. This caused some resentment among the ODSTs that remained throughout the mission.

The raid
The team was deployed via SOEIV from the destroyer. Entering the planet's atmosphere under cover of a meteor shower, one ODST, Checkman, was killed after his pod entered the planet's atmosphere at a bad angle. The surviving pods landed in close proximity to each other, but one ODST, O'Brien, landed in a swamp. Cal saved O'Brien from drowning as the latter's pod began to sink. However, as Cal had replaced him as sniper for the mission, O'Brien's contempt for the Spartan increased.

The team moved north through the ruins to gain a vantage point, taking photographs as they moved. Contact was made with a patrol of Unggoy led by an unidentified Jiralhanae Chieftain. Though the Unggoy were successfully neutralized, O'Brien was nearly killed and had to be saved by Cal. The Brute was thrown over a waterfall and presumed dead, but in fact survived and followed the team to their sniping position.

The team arrived at the sniping point with only two minutes before the Prophet arrived to inspect the ruins. However, they were ambushed by the chieftain and Cal was mortally wounded before she could fire on the Prophet. Despite his initial hesitation, O'Brien killed the Prophet with a single shot to the head from over two miles away.

Aftermath
Cal died shortly after the Prophet's death, giving Cortez the recordings of the ruins. These sparked interest within the scientific community after the Human-Covenant War, and the Department of Xenoarchaeological Studies at the University of Edinburgh was commissioned by ONI to research the ruins.

Cal's actions during the mission and her saving O'Brien's life many times until the loss of her own changed the team's thoughts and opinions on the Spartans. Upon their return to Kronstadt, the surviving ODSTs reacted aggressively to an Army specialist who suggested the Spartans were inferior to them based on Cal's death.

List of appearances

 * Halo Legends
 * The Babysitter