The undead are all creatures that are formerly deceased humans, but move and behave as if they are alive. They can be seen in a semi-spiritual form like the Apparitions or in the form of rotting flesh and bones like Zombies or Haunts. The Undead can be summoned by practitioners of necromancy, areas that the dead have been disturbed, or by curses. The Undead activity is usually a massive phenomenon as they tend to wander in groups, and when one corpse has risen from death, others are likely to follow. They can usually be found in tombs like the Bonehoard, near graveyards or unpopulated areas where they rest uneasy. All Undead creatures have an inherent hostility towards the living, though certain artefacts can have an influence over them. The walled off section of the Old Quarter is inhabited by a great number of undead.
They are horrific and quite difficult foes as they are fearless and never flee from battle. All Undead are very resistant to conventional weapons like swords and regular arrows and are also immune to knock-out gas.
The undead are almost always found in great numbers, and will never back down from a fight. Additionally, many conventional attacks, such as from a sword, Broadhead Arrow, or knockout gas from a Gas Arrow or Gas Mine often have no effect on them, making them dangerous and relentless enemies.
Undead have a strong vulnerability to bright light attacks such as from Flash Bombs, Explosive Weapons, fire, backstabbing, Holy Water, and special blessed weapons. Fire Shadows are extremely vulnerable to water based attacks.
- Most undead are believed to have been summoned through Pagan magic, Hammerites mention this connection in Deadly Shadows as well as a pagan necromancer had further admitted this notion via notes found in Old Quarter.
- According to a letter found within the abandoned Keeper facility of the Sealed Section, Keeper Andrus expressed concern regarding the Trickster and the danger he posed to the entire city and their order. Since Andrus was among the Keepers who sealed off the Haunted Cathedral, it is possible that the Cataclysm was related to the Pagan God.
- The Eye is believed to have played a part in the undead rampage of Old Quarter. It is an item related to the Trickster and it originated from the Haunted Cathedral before the disaster started[Citation Needed].
- Despite their hatred for necromancy, the Hammerites' deceased members have been occasionally brought back to life as the living dead: Haunts, Apparitions and possibly even Zombies. All these abominations can and are found within sacred Hammerite territories, and even Mechanist locations.