Before the Locust War, no one living on Sera's surface ever suspected that there were subterranean creatures capable of flight, certainly not creatures as large as Reavers. It is not even known how Reavers can fly as they have no wings; in fact, their entire biology has proven to be complex and confusing. The Reaver has a typically bulbous body structure and a small, raptor-like head. It has six long tentacles that may or may not have something to do with flight, however, the Reaver is capable of walking on these appendages when it lands. The tentacles end in thick bony claws which allow it to grasp the terrain and make effective close-range weapons, allowing the Reaver to crush and impale human combatants. There are also two small, hook-shaped limbs on the Reaver's "belly" that appear to be vestigial, though they may help the Reaver cling onto objects for easier landing.
Reavers are equipped with two seats: one for a Drone beastrider and the other for a Drone or Theron gunner armed with either a Hammerburst rifle or a Torque Bow. The Reaver is outfitted with its own weapons as well: a mounted machine gun and rocket launcher.
Reavers can be quite hardy opponents depending on the environment they are fought in and how many of them and other Locust are nearby, but they do have a vulnerable spot. A large red bulb is present on the creature's underbelly which can be destroyed with relatively little ammo expenditure. Destroying this bulb will kill the Reaver that much faster.