Reivers are enemies in Hexen.
They are flying, rotting corpses with the lower half of their body gone, and they wear armor and helmets. Reivers are only found in the Necropolis, the final hub of Hexen. They can start out either above ground or buried underground. They shoot fireballs and also leech health from players as a melee attack. Each Reiver possesses 150 hit points.
They can also sometimes be found in the secret level in the Necropolis hub, the Vivarium, and also have scattered use in the Hexen expansion pack, Deathkings of the Dark Citadel. The equivalent level that is the graveyard and feature level of the Reivers in this game is the Locus Requiescat.
The Reivers appear in huge, singular armies in the Necropolis level, and each time the player kills every available one the next wave is halved. WIth enough patience, health, and mana, it is possible to clear the entire level of Reivers before exploring it fully.