Buried Blade

The Buried Blade were a special operations unit of Sangheili tasked with intelligence-gathering, and served directly under the command of the Hierarchs.

Description
The Buried Blade were by-and-large irregular forces, always with an eye towards sabotage and intelligence gathering. Made up of highly-trained spies and assassins, Buried Blades were trained to blend in with a given population, where they proceeded to eliminate guards and officials, stir up civil unrest, and otherwise harm enemy movements. More critically, their operatives were also deployed on undercover assignments to watch Covenant officers who may harbor heretical beliefs or traitorous motives.

History
The Buried Blade came about as a concept during a pre-industrial era on Sanghelios, when a feudal kingdom of very contentious alliances faced off against an external threat. Many kingdoms refused to send any troops to the fight, citing the need to defend against their neighbors.

An exasperated king told them to send the troops and arm the serfs. Better than an army that sat around or paraded all day was a blade buried in a farmer's field and the promise that any invader would have his throat cut in the night.