Terror Demon

"The ancient texts describe the terror demons as unconquerable foes, the dreams of Diablo made flesh. They appear in shadow to torment their victims, and then...in shadow they vanish. The mere sight of one drove a Horadrim to madness, leaving him screaming and clawing at his eyes until the end of his days."

- Deckard Cain

Terror Demons are demon enemies in Diablo III.

In-game
Terror Demons are easily recognized by their sheer size and spiked form shaped after Diablo, Lord of Terror. However, they are of very dark color, and appear only at the moment of attack, so looking around for them will not help the player to avoid being ambushed.

Terror Demons are only encountered in Act IV, Pandemonium dungeons or Nephalem Rifts. They are often hiding in shadows, only appearing once the player comes close, leaving glass cannon builds at a severe disadvantage, with no means to prevent the ambush. They only have melee attacks, which are rapid and cause significant Physical damage, but their most notable ability is their curse applied on each damaging hit. This curse reduces all healing received by 25% for 10 seconds (used to be 75% at the time of game release, but proved to be overpowered, possibly the main reason why Act IV was run rarely in the first place).

Some Terror Demons can also disappear in case of danger, forcing the player to focus on other targets, and then come back to attack from unexpected direction. While invisible, Terror Demons cannot be harmed in any way.

Terror Demons usually attack in groups of two or more, or with a large retinue of Shadow Vermin. Be wary of multiple demons emerging from shadows at once, as their attacks can easily kill a hero if applied simultaneously.

As of Patch 2.1 (or 2.2), Terror Demons can be found in visible state, and they only rarely if ever use their vanishing ablity anymore.

Uniques

 * Aspect of Terror
 * Dread Stalkers
 * Inquisitor Sebacious
 * Iskatu, Minion of Diablo
 * Malefactor Vephar
 * Nekarat the Keywarden
 * Orlash (Rift Guardian)
 * Shadow Servant (Set Dungeon)