Dwemer Animunculi (also known as Dwemer Constructs, Dwarven Automatons, Dwemer Centurions, and Dwarven Robots) are mechanical golems created by the Dwemer. Made out of Dwarven metal, animunculi were used as war machines and guards. Many of them continue to protect the underground ruins of Dwemer cities long after the disappearance of their creators in 1E 700. They are commonly encountered by scholars and adventurers who venture into the ruins; the animunculi perceive them as invaders, and even worker constructs will attack trespassers on sight.
Animunculi function on steam power and magic, and usually require a soul. For the constructs in Morrowind, this simply required tapping into the power of the Heart of Lorkhan. Animunculi taken from Morrowind are typically unable to function in other parts of Tamriel. Even after the destruction of the Heart's physical shell in 3E 427, they continued to work. Constructs in other parts of Tamriel, such as in Skyrim and on the island of Solstheim, are equipped with individual soul gems or dynamo cores. It is unknown how the constructs on the island of Stros M'Kai obtain power.
Research in the Second Era suggested the Animunculi found in much of western Tamriel were powered by soul gems. They only deactivated when removed from a ruin as a security measure, but with specialized tools and knowledge it was possible to reprogram them to perform other tasks.
There are many types of animunculi found in Dwemer ruins all over Tamriel.
Dwarven Spiders (also known as Centurion Spiders) are small, arachnid-like animunculi, and are very common in Dwemer ruins. They will often be found working on rocks or other objects. They can attack intruders using blasts of lightning, or by emitting poisonous gases from a bag.
Dwarven Spheres (also known as Centurion Spheres) are a common form of Dwemer Animunculi that have proven to be agile fighters, and are much stronger than the smaller Dwarven Spider. Dwarven Spheres patrol ruins in a spherical form until they encounter an opponent. At this point, they will erect into their semi-humanoid form and attack. There are different kinds of Centurion Spheres. Some are armed with an extendable sword and a shield, while others have a crossbow mounted on their off-hand arm instead.
Centurion Archers are a rare type of construct found only in Bamz-Amschend, an ancient Dwemer city located beneath Mournhold. They are similar to Centurion Spheres, but are equipped only with crossbows.
Dwarven Sentries are spherical animunculi found in the Wrothgar region of High Rock. Roughly half the size of their Dwarven Sphere counterparts, Sentries patrol ruins in a similar fashion, extending their necks to emit shocks in order to incapacitate intruders.
Dwarven Centurions (also known as Dwarven Mechanical Giants or Steam Centurions) are heavily armored constructs with either an extendable mace on one arm or a hammer on one arm and a spring-loaded spike in the other. Some are even able to emit a scalding blast of steam. They are not as common in Dwarven ruins as the lesser Dwarven automatons. The book Ruins of Kemel-Ze implies that the constructs have a weakness to frost and magic attacks, due to the water/steam that drives them, although they are highly resistant against fire, frost, and shock. They are sometimes found attached to a charging gantry when not in use. A giant centurion was once located on Stros M'Kai, but was defeated by Cyrus in 2E 864 when he attacked its heel, its only weak point.
Numidium (or Anumidium), also known as the Brass God, the Prime Gestalt, the Brass Tower, Walk-Brass, and Big Walker, was a gigantic golem of Dwemer origin. Numidium was constructed by Tonal Architect Lord Kagrenac to be a new god, powered by the Heart of Lorkhan, to retake Resdayn from the Chimer and make the Dwemer race immortal. The Dwemer disappeared from Tamriel before Numidium could be activated, though their disappearance is possibly directly related to this endeavor.
Numidium was, in practice, a weapon of devastating power; it was used by Emperor Tiber Septim to complete his conquest of Tamriel at the end of the Second Era, but was destroyed afterward. The golem was rebuilt and reactivated centuries later, and became the center of the phenomenon known as the Warp in the West, after which it was destroyed again. A second Numidium, Akulakhan, was partially constructed by Dagoth Ur a few years later. However, the destruction of Kagrenac's enchantments on the Heart of Lorkhan prevented its activation. Akulakhan was based on Numidium's design.