Revenant

Revenants are monsters introduced in Doom II. They have the form of walking skeletons that fire two sorts of missiles: unguided and homing. The homing missiles can be identified by their smoke trail. They can also use a short-range punching attack that resembles karate, complete with an exaggerated punching sound effect.

If a Revenant is within 196 units of its target, it won't use its projectile attack unless attacked and hurt, which makes it counter-attack with its missile.

According to the manual:
 * Apparently when a demon dies, they pick him up, dust him off, wire him some combat gear, and send him back into battle. No rest for the wicked, eh? You wish your missiles did what his can do.

Revenants are humanoid and appear to be wearing frayed short trousers; however, it seems clear from the graphic that they are naked from the waist down, but decayed and bloodied. Revenants appeared in Doom 3, and were definitely naked, albeit the body is entirely skeletal with some sort of gelatin-like coating.

In the Doom novels, Revenants are unchanged for the most part, though appear to have a layer of skin on their bodies, much like the Doom 3 Revenant. They also wear red shorts. They are believed to be an early attempt by the aliens to genetically grow human duplicates- albeit a failed one. The fact they wear clothes when none of the other monsters do may back up this belief.

Strategy
Revenants' fireballs are very powerful and when homing, nearly impossible to dodge when out in the open. Fortunately, the pain chance of a Revenant is rather high, so a chaingun will generally suffice against a single Revenant and prevent it from attacking. When fighting larger groups, it is useful to use a plasma rifle, BFG or rocket launcher. It is useful to keep moving, as this will prevent the non-homing missiles from reaching the player. Revenants are very fast, so the player must be sure to keep their distance. The Revenants' punch attacks are fiendishly powerful and can easily down the player with a few punches. If pillars, walls, or other obstacles are available, then they will be useful as barriers for blocking homing missiles.

Doom RPG
In Doom RPG, the Revenant appears as a class of monster. There are three variations, identified by color:


 * Ghoul (normal but with green "pants")
 * Fiend (blue)
 * Revenant (normal colors)

Interestingly, the designers of Doom RPG must have believed that the Revenant was wearing pants (see comments above), as the Ghoul variation has the "pants" recolored green.

Appearance statistics
The IWADs contain the following numbers of Revenants: