From Halopedia, the Halo wiki
Bloodfuel Brutes are equipped with a form of backpack and with unidentified weaponry who lead a couple of Unggoy Bloodfuel. These weapons are seemingly capable of "siphoning" the health out of the target of the weapon and healing the user wielding them.
The Bloodfuel Grunts are classed as core infantry, and performs well against infantry, vehicles and aircraft.
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