Cameleoline is a refractive chemical substance that morphically blends its colouration into the surrounding area. It is often woven into cloaks and smocks, or more rarely, as a coating over armour plate. Its properties aid with concealment during covert assaults. This archaic material is most likely a holdover from the Dark Age of Technology and has been in continuous use since at least the Great Crusade and Horus Heresy eras during the late 30th and early 31st Millennia. Specially-fabricated Cameleoline Cloaks were primarily used by Legion Reconnaissance Squads, comprised of experienced Space Marines who were expert in operating independently and often deep behind enemy lines. These specialised troops were the eyes and ears of their Space Marine Legion in the field. For this task, they were armed and equipped with a variety of specialised wargear, including long-range weaponry, sensory Auspex and Cameleoline stealth gear.
In the late 41st Millennium, Cameleoline is still utilised by the Scout Marines of the Adeptus Astartes, to aid them in the stealthy infiltration of enemy positions or to fight as lightly armed skirmishers ahead of the rest of their Chapter. Wearing Cameleoline Cloaks, these Scouts are able to operate behind enemy lines, set ambushes for their foes, determine the enemy's movements, and gather what information they can about their opponent's plans.
A notable mortal Imperial military formation that also makes use of Cameleoline technology is the Imperial Guard's Tanith First-and-Only Regiment. Cameleoline is also utilised by other Imperial armed forces as well, in the form of tarpaulins to help conceal large pieces of military equipment. These thin, resilient tarpaulins are made of sheets of photosensitive, colour-shifting fabric that can take on the appearance of their surroundings. Issued in five metre-by-five metre sheets, Cameleoline tarps can be hooked together to hide anything from a Land Speeder to a Rhino armoured personnel carrier, to an entire encampment.
- Codex: Space Marines (5th Edition), pg. 100
- Deathwatch: Rites of Battle (RPG), pg. 145
- Imperial Armour - The Horus Heresy - Book One: Betrayal, pp. 207, 236
- Only War: Hammer of the Emperor (RPG), pg. 29
- First and Only (Novel) by Dan Abnett
- Courage and Honour (Novel) by Graham McNeill