In addition to being battle-brothers to their fellow Space Marines, Techmarines (Frater Astrotechnicus) also serve as mechanics and technicians to their respective Chapters, similar to the Enginseers who serve in the Imperial Guard.
In addition to their engineering roles, Techmarines are often the pilots of Space Marine gunships and aircraft.
Space Marine Chapters identify prospective Techmarines from within their own companies, favouring those who show the greatest affinity for machines. These aspirants are then sent to Mars for thirty years of training, where they are taught the lore of the Machine God, how to divine the Runes of Engineering and the Liturgy of Maintenance. This great body of lore must be fully understood and committed to memory by the novice Techmarine. A great deal of the thirty years of instruction involves learning each of the many and intricate maintenance rituals and hymns by heart. The rituals, furthermore, have variations to cover every conceivable circumstance in battle. A fully-fledged Techmarine is expected to be able to "feel" the pain of a damaged machine and heal it. After completing the training, the Techmarine is ordained, and returns to his Chapter. Techmarines pledge allegiance to both the Cult Mechanicus and their Chapter, which makes them something of an oddity among their battle-brothers.[Needs Citation] The highest position among the Techmarines is held by the Master of the Forge.
A Techmarine's Power Armour is modified to accommodate his cybernetic enhancements and his armour's backpack is also upgraded with several servo-arms and mechadendrites. His armour bears the rust-red colours of the Adeptus Mechanicus, but his Chapter badge is retained and displayed on one of the shoulder guards, so as not to disrespect the armour's spirit. Techmarines are able to wear full servo-harnesses, huge harnesses armed with servo-arms, plasma cutters, and flamers. Techmarines can also be accompanied by a retinue of Servitors; Gun Servitors, Combat Servitors, and Tech Servitors. Their usual weapon is a Power Axe with the Adeptus Mechanicus symbol on the head, as both a symbol of rank and as a weapon.
- Grey Knights Techmarine - Grey Knights
- Iron Father — Iron Hands
- Forge-Wright — Sons of Medusa[8b]
- Iron Priest — Space Wolves
- Brother-Adept — Star Phantoms[8a]
- Abrahim Kobal — Salamanders, see also his quotes
- Aviren — Iron Hands
- Martellus — Blood Ravens
- Paullian Blantar — Iron Hands
- Sevano Tomasin — Ultramarines
- Vexos — Ultramarines
- Skvarl Cogfang — Space Wolves
- Shen'ra — Salamanders
- 1: Codex: Space Marines (5th Edition), pg. 71
- 2: Warhammer 40,000: Compendium, pg. 131
- 3: Codex: Space Marines (4th Edition), [Needs Citation]
- 4: White Dwarf 346 (UK), [Needs Citation]
- 5: Codex: Chaos Space Marines (4th Edition), pg. 35
- 6: Liber Apocalyptica: Forces of the Space Marines, pg. 40
- 7: Codex: Dark Angels (6th Edition), pg. 32
- 8: Imperial Armour Volume Ten - The Badab War - Part Two
- 9: Death From the Skies (7th Edition) — Adeptus Astartes
- 10: Strategy Cards for Planetary Empires expansion game, card "Vortex Grenade - Minor Stratagem", (saved archive page, dated February 2011, last accessed 9 September 2017)
- 11: Index Astartes: Volume I (Background Book), section Techmarines, subsection Equipment and armour
- 12: White Dwarf 291 (UK), Index Astartes - Cult of the Machine God, Techmarines of the Adeptus Astartes, pg. 15
- 13: Codex: Grey Knights (8th Edition) pg.44