The Taghmata Omnissiah (translated from Lingua Technis as that which is divinely ordered for war) was a type of military operational force of the Adeptus Mechanicus during the Great Crusade and Horus Heresy. The "third arm" of the Mechanicum armed forces alongside the Collegia Titanica and Skitarii, the Taghmata Omnissiah was a type of feudal military organization enacted in times of war and urgency. It represented the feudal power structure that each Forge World could muster in times of battle. This type of feudalized command was necessary, as at the time of the Heresy the Forge World's of the Mechanicum were each a kingdom in and of itself with its own complex hierarchies and traditions.
The Taghmata Omnissiah included militant Tech-Priests, Cybernetica, Knights, Combat Servitors, Thallax, Myrmidon's, Tech-Thralls, Ordinatus engines, and a wide variety of other miscellaneous forces at a Forge World's disposal.
Since the Heresy, the Taghmata Omnissiah of Forge Worlds have effectively been reorganized as Cult Mechanicus Battle Congregations. They utilize the same forces and general command structure as the Taghmata.
Military forces and organizations that fall under the purview of the Taghmata Omnissiah include:
- Magos Militant
- Legio Cybernetica
- Knight Houses
- Centurio Ordinatus
- Ordo Reductor
- Auxilia Myrmidon
- Autokrator - Ground armor (including the Krios and Triaros), mobile artillery, and pioneer units.
- Macrotechnia - Included Enginseers and Tech-Thralls
- Munitoria Logis - Providers of wargear, equipment, Lexmechanics, and Servitors
- Lacyraemara - Included indentured servants
- 1: The Horus Heresy Book Three - Extermination, pgs. 200-205
- 2: Codex: Cult Mechanicus (7th Edition) - Cult Mechanicus Battle Congregations