Wraith

The wraith is a monster in Doom 3 and its expansion packs. Wraiths are limited to melee attacks with their falx-like arms, and run forward to attack the player. They possess the ability to teleport, disappearing for a few seconds before reappearing several feet ahead of their previous position. The wraith can be easily mistaken for an imp while it is being summoned. Unlike an imp, wraiths are hunched over and present a lower target profile. Furthermore, wraiths have only two eyes and a set of mandible-like jaws, and anatomically resemble a bat more than a human. The wraith first appears in the EnPro Facility.

Tactics
Like imps and maggots, wraiths are mid-level humanoid-type demons who are individually relatively easy to dispatch, but who can attack in groups of up to several in the same area. Wraiths cannot be killed while teleporting. However, it takes them about a second to disappear or reappear, during which they cannot attack and are vulnerable to being damaged or killed.

It is a good idea to throw a grenade their way. Another good tactic is to wait for them to get close and eliminate them with the chainsaw or the shotgun. In addition, they can be easily eliminated with the machine gun or plasma gun from medium range.

Wraiths are extremely vulnerable to being chainsawed during their second-long appearing or disappearing animations.

Trivia

 * According to the Making of Doom 3 book, id Software wanted the wraith to form out of a cloud of insects, to hide in bodies and such, but this concept was scrapped since the player would not be able to tell what the cloud was in the game's dark environments.
 * The wraith's teleportation ability is not exactly teleportation. For one, it is not instantaneous. Also, when they teleport through doors, the doors will respond to their presence and open up. Furthermore, their footsteps can still be heard after they disappear. This suggests that wraiths do not actually teleport, but rather "phase" into a state of existence where they cannot be seen or attacked.