A Kill Marine is essentially what a Space Marine from the Deathwatch is called. Grouped together and they become a Kill Team. However, since the Deathwatch is a highly pragmatic and largely autonomous force, with a large myriad of xenos threats plaguing the entire Imperium, not every planet could have the luxury of hiring out even a single Kill Team. Still, the Deathwatch is a generous bunch and is willing to rent out a single Kill Marine to investigate and deal with any interesting or odd xenos activity in a backwater Imperial world. Under these kinds of circumstances a Watch Captain may elect to send a single Space Marine, a specially trained "Kill Marine" skilled in solo operations, to investigate and exterminate where possible or to call in backup where it is truly needed.
Overview AKA Your Dudes
Kill Marines are naturally denied the reliable supporting firepower of their Battle-Brothers and fall back on the stealth and infiltration techniques they first mastered as Scout/Initiates to perform their duties. Scout Sergeants often make superlative Deathwatch Kill Marines with little additional training but these specialists are drawn from all ranks of the Deathwatch as needed. A certain independence of thought and great strength of spirit are in many ways more important than exceptional stealth skills for a Kill Marine. A Kill Marine must possess the right temperament to operate for long periods cut off from their kind and from the sacred touchstones of their Chapter.
Space Marines ordinarily live a cloistered existence in their Fortress-Monasteries. Their contact with the outside world is normally limited to fighting wars in it and their interactions with humans only come in chance encounters on the battlefield. By contrast a Kill Marine has to interact frequently with the existing authorities and power structures of the Imperium, often acting as a direct representative of the Deathwatch before Planetary Governors, war councils and ruling bodies of Adepts.
Kill Marines spend time living alongside those they must ultimately defend, sharing their trials and seeing the world through their eyes. In their missions a Kill Marine will make allies and enemies of many that they meet, and hear tales that would never reach a Watch Fortress. He might become involved in events that ultimately have little to do with the Deathwatch directly but rebound to the greater security of the Imperium. In this way the remote Deathwatch maintains a limited connection to the great masses it is charged to protect.
In practical terms the greatest step a Kill Marine must take is to secure travel between the stars as Deathwatch vessels can rarely be spared for their direct deployment. Interstellar ships are such rare and precious things that even the word of a Space Marine will not turn one from its course (yeah, trying saying “no” to his face and your replacement will be much more cooperative). More militant Battle-Brothers have sometimes opted for the expedient of capturing a pirate vessel and forcing its crew to do their will, exterminating their unwilling hosts once they reach journey’s end. However many less drastic opportunities exist for a Kill Marine that is prepared to think more broadly. He might travel aboard Imperial Navy warships and Rogue Trader vessels for example, or join the retinue of an Inquisitor for a time if it will serve his purposes. To do this the Kill Marine may have to use his natural humility to ask, and not demand, his passage by offering his assistance in trade for reaching his destination.
Imperial authorities will usually welcome the opportunity to gain access the knowledge and experience of a Space Marine for their own purposes in some vexing matter. The singular skills a Kill Marine can bring to bear are liable to open whole realms of possibility that were previously out of reach to a Rogue Trader Captain or an Inquisitor. A previously unknown and potent player entering the game can be invaluable for their schemes. The guarantees of transportation to an undisclosed location that a Kill Marine may ask for are a small price to pay to secure his help.
Kill Marines do often forego power armor and use non-standard weaponry of a somewhat stealthier demeanor than the sacred boltgun and holy chainsword. They maintain that this practice is born of practicality when they are commonly moving through environments designed for an unarmored man, and that employing more easily concealed weaponry only serves to soften their otherwise intimidating and warlike aspect. It is to be expected that such peerless warriors would adapt to their circumstances by honing their stealth and unarmed combat skills to exceptional levels so that they can slay quickly and quietly in case of trouble.
It is true that Kill Marines are often sent on missions obscure to their Battle-Brothers in the Deathwatch and even to themselves. The Librarium and the Apothecarion can layer mental blocks and hypno-conditioning into a Space Marine’s mind to make it receptacle for the most sensitive knowledge. Secret orders or communiqués that a Watch Captain will not entrust to Astropathic communication may be buried deep in a Kill Marine’s subconscious for him to transport to another Watch Fortress. A Kill Marine may carry, knowingly or unknowingly, relics or other items of key importance for delivery into the hands of specified individual. They may be assigned to guard an individual while having pre-programmed assassination protocols in place to eliminate them if the call arises. Some whisper that these enigmatic figures have even dealt directly with aliens, a feat that would surely require extreme Hypno-indoctrination for a Deathwatch Space Marine to achieve.
Tl;dr, a Kill Marine is essentially one of the best units in role-playing as he is basically a blank-slate Space Marine with the privilege of traveling almost anywhere, carry any sort of weapon and have different personalities because he is a Deathwatch, not constrained to a specific Chapter's customs and rituals. He is able to wear without or with power armor if he chose so and is allows certain liberties on how he would conduct his missions. He is essentially Your Dudes in one compact form.
|Forces of the Deathwatch|
|Command:|| Forge Master - Keeper - Deathwatch Chaplain |
Watch Captain - Watch Master - Deathwatch Epistolary
|Troops:|| Deathwatch First Company Veteran - Deathwatch Champion |
Terminator Squad - Veteran Squad - Kill Team - Kill Marine
|Walkers:||Venerable Dreadnought - Deathwatch Dreadnought|
|Vehicles:|| Bike Squad - Rhino - Razorback |
Land Raider (Land Raider Redeemer - Land Raider Crusader)
|Flyers:||Drop Pod - Corvus Blackstar|
|Allies:||Space Marines - Primaris Marines|