The Reasonable Marines are what Space Marines would be if 40K was less grimdark, the Imperium was a benevolent governmental body, Tau were happy Koreans and Abaddon was competent. They wear camouflaged power armor, fight using careful tactics that make heavy use of cover, and are the epitome of practicality. They also seek to avoid combat whenever possible and are adept diplomats. However, in its own way, being clever badass can be even cooler than balls out badass.

They're one of the legions from the lost Primarchs, their primarch currently wandering around dazed and confused in an alternate reality never to be seen again.

Reasonable Marines operate with efficiency. They fulfill their orders and fight valorously and without hesitation, unless they see a more sensible solution that can fulfill the same goals. They always prefer to force a surrender rather than routing the enemy, and take prisoners to interrogate them humanely and use as bargaining chips. It's not so much that they don't like to fight as it is that they're not bloodthirsty - they understand that fighting puts their own in harm's way and is detrimental to their cause due to its great expense.

Seeking vision without prejudice, yet understanding that this ideal may be unattainable, the most important thing to them is to successfully serve the true interests of the Imperium. If this involves negotiating with or even protecting xenos, then that is what they will do.

Heroism and a thirst for glory are frowned upon in their ranks, as they are wasteful of personnel and other resources, and perpetuate the conflict. They wish to create a stable end to the war with mankind in a comfortable and free position. Victory is their goal only insofar as a civilization vanquished in this conflict is sure to be subjugated or annihilated.

In battle, they employ sophisticated and highly coordinated group tactics not commonly associated with normal space marines. Their armor is painted to blend into their environment in order to limit visibility like being camouflaged in multiple spectra so that, for example, their heat signature is harder to detect. No matter how cool it looks, a Reasonable Marine still needs to request permission from their commanding officer to carry nonstandard equipment into battle, and must justify this in a way that demonstrates its effectiveness in combat.

If Reasonable Marines were to be considered an actual Marine faction, they would quickly become one of the most infamous for rage inducing as their approach to war in the 41st millennium is radically different than the typical Wardian space marine chapter. Seeking to always operate at utmost efficiency, minimizing casualties and avoid pyrrhic victories, Reasonable Marines aren't likely to even pop their heads up until the odds are in their favor. The Deathwatch comes close to being Reasonable Marines in terms of tactics, but they are only geared towards Xenos, are rarely diplomatic, and are under the direct command of the Inquisition, so no.

Also, the Alpha Legion back in the Great Crusade era might have been similar to them, but at the same time the Alpha legion has always been about mind-f uckery and deception and not as heavy as the Reasonable Marines in the use of cover and stealth. But again, as said before the loyal Alpha legion might have been the closest thing the Imperium ever got to the Reasonable Marines.

Favoring a ridiculously mechanized approach to protect their own, chances are somebody who proves stubborn enough to force Reasonable Marines into combat would find themselves being bombarded from orbit for days on end. In this example, consider a force more prone to reason like Imperial Guard, Tau or Eldar. The following siege strategies don't apply to more heavily armored foes like Chaos Marines, Necrons or even other Space Marine chapters. If the opponent in question persists, a merciless aerial campaign will be waged against them by Stormraven gunships and other such aircraft, aiming to force a surrender while simultaneously providing a distraction for initial drop pods to seed scouts and devastators in their territory. If that doesn't work, that's when things begin to get ugly.

Operating under the confusion of constant bombardments and propaganda drops, the Reasonable Scouts would act as pathfinders for the Devastators. Digging in to key positions, the sniper fire begins, killing commanders and high ranking officers to further increase the chaos and confusion amongst the ranks. Other scout units wage bitter guerilla campaigns, most often by slipping behind enemy lines before cutting supply routes and other means of disrupting enemy logistics. A final, orchestrated bombardment of dozens of krak and frag missiles courtesy of Devastator squads topples defenses and shatters morale, at least if things go according to plan. If the enemy's commanders have evaded assassination and continue to rally their troops to the cause, the Reasonable Marines engage in one final show of force.

Dozens of Land Raiders and Predators are deployed, now free to move ahead free of high-risk scenarios. Rolling up at the opponent's front door, heavy vox systems broadcast final warnings.

It is here they are given an ultimatum - surrender and resolve things diplomatically, or be pacified.

If this fails to work, the action begins. Infiltrated squads of Tactical Marines storm the enemy, subduing them under a hail of shock bolts, stun grenades, and taking officers prisoner. More prisoners are taken off to be brought up to the Reasonable Marine ships to serve as bargaining chips while tanks below deploy hydro-cannons with intensely freezing waters to pacify infantry and use traditional weaponry to pick apart enemy armor formations. Tech Marines scurry back and forth erecting defenses and surface-to-air missile silos in case of enemy reinforcements. What cannot be captured or fortified, is destroyed with maximum efficiency and a minimum of fuss. At this point, it is merely a question of wearing the opponent out.

Even in the heat of battle, Reasonable Marines cleave to their principles and creed. You will not see chainswords or power weapons being brandished within the ranks of these Astartes. Assault Marines are clad in riot gear and equipped solely with shock mauls and stun grenades to apply a reasonable degree of force necessary to force violent brawlers into submission. In times where the enemy knows no reason such as the Tyranids or more fanatical factions of Chaos Marines such as the Word Bearers, these troopers wield traditional weaponry with full intention to kill off threats. A few of the commanders considered extreme and naively optimistic even in the eyes of the other Reasonable Captains have been trying to find ways to reason with the Necrons after initial shocking and absurd reports were confirmed of Blood Angels actually managing to ally with them.

Given the Reasonable Marine's radically different outlook on the galaxy they wage war in, it's not too surprising that the traditional dispositions the Space Marines possess are also radically different. This isn't necessarily a good thing for them, however, as the realm of 40k isn't one that is particularly enamored towards reason. Outside of their own systems, the Reasonable Marines are painted as a threat to the Imperium by the High Lords of Terra and Inquisition, who fear that such reason coupled with the iconic might and position of an astartes chapter could quickly bring about another mass heresy. Thus, in a twist of fate, the Reasonable Marines are treated as a traitorous extremis group and find themselves in conflict with the rest of the Imperium almost more often than the alien or heretic. Relations with the other Space Marine chapters are generally unstable, but still a step up from the Inquisition and Imperial Guard forces.

• The Inquisition

The two factions abhor one another, seeing the other as a taint to what the Imperium should rightfully be. The Reasonable Marines find clashes with the Inquisition particularly unpleasant and generally stay out of their way, though they share a common hatred of demons and the pervasive warp, and in turn the Inquisition is happy to make sure the rest of the Imperium is largely ignorant of the chapter's existence. The Grey Knights, however, have shown remarkable reasonableness for operating alien devices in their all-out fight against daemonkind, thus both the reasonable marines and the knights have each earned each others grudging respect and tolerance.

Clashes with the Inquisition mostly occur in the form of the Sisters of Battle whenever one steps on the others toes. With a particular disgust towards the Sisters overzealous and often vicious approach to dealing with conceived 'problems', it is not uncommon for Reasonable Marine raiding forces to crash an Adeptus Sororitas purge they deem "overkill". In these scenarios, the Marines act more as a rescue party, rounding up as many of the purge's targets as possible and retreating to judge them in a more civilized manner or even occasionally rehabilitate the intended targets. Aside from the Traitor Marine Legions, Imperial forces attacking civilians are the only human force the Marines will bring all traditional lethal weaponry to bear against.

• Imperial Guard

The Reasonable Marine's relations to the Imperial Guard are colorful, to say the very least. While relatively quick to ally with one another, it is never too long before the two factions command structures begin to butt heads with one another over some breach in rank or protocol. The Imperial Guard is generally the more reluctant of the two when it comes to buddying up, mainly because contact with the Reasonable Marines always end with swathes of men attempting to defect to the Marines. Commissars have an unusual tendency to flare up the normally calm and reserved Reasonable Marines with their approach to treating guardsmen. This results in headaches for everyone as clashes between Marines and Commissars are inevitable and generates a plethora of paperwork.

When the Guard and Reasonable Marines go to war against one another, the result is a war of attrition that rages on until one of the sides goes "F uck it", takes his ball and goes home. It is also an example of how the Reasonable Marine's reason can sometimes do more harm than good as on their side they put great effort into minimizing casualties among the Guard. When coupled with propaganda, this causes a fair portion of the Guard to hesitate in fighting their fellow loyalists and as mentioned earlier causes plenty of defects and treason in the process.

However, it also causes another large portion of the Guard to attack with greater ferocity, knowing their foe is reluctant to engage with full force. Both forces boast massive manpower, but the difference in tactics means either side can often come out triumphant. The biggest danger to any Guard force going up against the Reasonable Marines is their tendency to mix mind games and diplomacy, as the Marines opt to try and turn the whole IG Force against its leaders or sometimes even talk the whole entire division into switching allegiances. Utilizing Commissars to reinforce the chain of command often ends up doing more harm than good as the Marines are quick to play up the average Guardsman's resentment of such authority figures.

Like the Imperial Guard, the Reasonable Marines relations with the other chapters vary widely. However, recorded incidents of Reasonable Marines engaging other Loyalist Marines are unpleasantly common. Indeed, the Reasonable Marines have not forgotten the kinship they ought to still share with the other Chapters, and harbor a particular bitterness towards fighting them. In these cases, the adversity arise not so much out of pure hate as many of the Chapters are aware of them and skeptical of the Inquisition's propaganda. It arises in conflicting goals. While some Chapters team up with the Reasonable Marines just as often as they fight them, others are wholly incompatible with them.

• Black Templars

Like the Sisters of Battle, the Black Templar's zealotry and lust for violence is too much for the Reasonable Marines. Coupled with their massive legions of soldiers, the Reasonable Marines outright avoid contact with the group unless forced to due to matters of importance or during extraordinary circumstances.

• Blood Angels

The Reasonable Marines frown upon the Blood Angels, considering them more like beasts than Space Marines. Given the unstable nature of their geneseed defects, and their borderline psychopathic affinity for close combat, Reasonable Marines seldom deal with the Angels. However, this opinion is conflicting as some captains have become fascinated by stories of the Chapter somehow managing to ally and part peacefully with the Necrons: a foe the Reasonable Marines long believed to be wholly unreasonable. However, such interest is discouraged by more senior battle-brothers in the Chapter.

• Dark Angels

The Reasonable Marines are distrustful of the Dark Angels, not beyond working with them, but far from accepting. While the Reasonable Marines are no stranger to being scrutinized as treasonous, the Dark Angels show a sort of morbid love in persecuting threats to their credibility. Such behavior means they have something to hide, and the Reasonable Marines keep their distance, especially out of caution that the Dark Angels might lash out under the belief that they could by some chance be similar to the Fallen or worse; harbor some of them- which given the way the Reasonable Marines recruit, does not help dispel these suspicions.

• Imperial Fists

The Reasonable Marines have no problems with the Imperial Fists and find great value in their defensive capabilities. In times where relations are smooth, it isn't uncommon for the two to collaborate in exchanging knowledge about the others' combat specialization. They still have their occasional disagreements, but they are often brief and usually resolved peacefully.

• Iron Hands

While the Reasonable Marines admire the Iron Hands unflinching tenacity and resolve, they despise how rigid and uncompromising they are. The chapter refuses to yield ground in battle even when it would be beneficial, and in victory completely eradicate their enemies, even if they have surrendered and are begging for mercy. They also see the Iron Hand's obsession with modifying their bodies with bionics as unhealthy and irrational. When the two come to blows a battle is always immediate as the Hands refuse any and all attempts at negotiation. In these instances the Reasonable Marines must regrettably resort to their more deadly armaments, the Iron Hand's enhanced physiology coupled with their many bionics rendering most non-lethal weapons useless.

• Raven Guard

While the Reasonable Marines consider the Raven Guard fierce rivals in the aspect of covert ops and tactics, this is also the same reason the Reasonable Marines respect the Raven Guard, and they often go to great lengths to stay up to speed with their tacticians. The Reasonable Marines still get in scrapes with the Raven Guard, but more often than not, in a more competitive manner than truly aggressive. However, on the rare occasion that the two chapters do get locked in conflict, it results in painstakingly long, lethal guerrilla campaigns fought almost entirely beyond the naked eye. Still, the times where the two share a cause are often enough that the they are more likely to come to the others' aid, than to oppose them, becoming in those times a truly terrifying and utterly lethal alliance to be reckoned with. In this they are a rare example of a friendly rivalry between chapters.

• Salamanders

The two could not be of greater opposites in terms of approaches to combat specialty and tactics, but the two chapters share a high regard for prioritizing human lives over destruction of the enemy. This is why they get along very well and will work together easily enough. Conflict does occasionally rise, but they are easily diffused between the like-minded groups.

• Space Wolves

Relations with the Space Wolves have not been particularly for the better. Like, at all. Not along the same vein of disaster as Black Templars or Blood Angels, the Reasonable Marines still have never worked well with the Wolves. The two share a common hatred of the Inquisition, so they see eye to eye on at least one topic, and might be all that keeps them from being wholly incompatible. But the Wolves obsession with melee, drunkenness and, well, wolves, doesn't go well with the Reasonable Marine's doctrine. They could ally, but probably under circumstances where they both share a common enemy. Would make great a buddy-cop action-comedy team.

• Ultramarines

While the Reasonable Marines are ones who admire enforced tactics and strategies, the Ultramarines and their codex are just another chapter to them, one they are particularly indifferent towards. They are easy enough to get along with and in comparison to some of the other chapters are preferred chapter. But in terms of overall ability, they find the Ultramarines lacking, except in arrogance. The distaste has arisen from several occasions where the two did work together, only for the Ultramarines to take all the credit. Since then, even the Reasonable Scouts view them with a sense of ire.

• White Scars

Another chapter the Reasonable Marines are fairly indifferent on, having nowhere near as much contact with them. They find the chapter's hit and run tactics highly effective and do occasionally emulate these tactics with fleets of landspeeders, but ultimately the White Scars have had little history with the Reasonable Marines and there isn't much that can be said of the relationship between the two.

• Blood Ravens

For the most part, the Blood Ravens and the Reasonable Marines find themselves as simple allies, fellow Astartes in service. However, any further bonding is hampered by one simple problem: the Blood Raven's fetishistic approach to battlefield scavenging. While the desperation of an unofficial, understrength chapter, especially one lacking in ties to forges of their own, to use whatever it can find is understandable (and, in fact, quite familiar) that does not change the fact that the Ravens have a history of looting Reasonable Marine casualties for equipment and prized relics. While outright hostilities are rare, Reasonable Marines must keep a close eye on the Ravens when one of them gets to close to their armory. Though some reasonable commanders trust them to an extent all Blood Ravens must stay outside of a 10 mile radius around all reasonable armories or relics, or anywhere else they keep store war gear or supplies. So they tend to stay closer to the enemy to TRY and make it harder for them to pillage their bits.

• Eldar

As with all other forces of the Imperium, the Reasonable Marines are naturally distrustful of the Eldar. However, the Chapter has come to accept that it is very possible the Eldar possess knowledge and foresight of events that they do not, and as such give them a bit more leeway and take heed of their warnings. However, the Reasonable Marines refuse to be used as unwitting pawns and do not hesitate to bring force into the equation if there is evidence that they are being treated as an expendable asset (as the Eldar often do when they deal with 'lesser' races). While they generally apply the same ethics they treat all other races with, the Reasonable Marines have often resorted to abducting and taking Farseers, Warlocks, or Autarchs hostage to make it clear that they will not be used.

• Orks

The Orks are beyond reason and beyond even the most basic forms of negotiation. As such, the Reasonable Marines have excluded them from the ethical approach to warfare they exhibit with other races. However, the more 'kunnin' Orks often give the Marines a challenge in guerrilla warfare and as such dealing with high priority targets like Kommandos are treated with the same sporty enthusiasm they would show when competing with the Raven Guard.

• Tyranids

Unlike the Orks, who the Reasonable Marines take a more laid back approach to dealing with, Tyranids are a considered a top-tier threat. No holds barred- shoot to kill. The sole race that the Reasonable Marines will bring out the flamers to use on, the Chapter will pursue the routing of the Tyranids with such dedication that they are willing to side with almost any other foe long enough to flush them out and destroy them. As creatures with heavily advanced senses and innate psyker abilities that defeat much of their stealth, the Tyranids are the only race that the Marines will abandon their traditional doctrine in favor of a separate codex's worth of tactics; designed specifically to eliminate them.

• Tau Empire

While the Reasonable Marines refuse to abandon the Imperium and as such have no intention of joining their Empire, the Tau are often a welcome change of pace for the chapter. The Reasonable Marines are quick to aid the Tau in situations that do not concern the Imperium, and in return the Tau Septs generally co-exist peacefully with the chapter. Trade is common between the worlds of the Chapter, and the Tau, and the Marines are willing to humor the Tau diplomats attempts at swaying them towards the Empire, if halfway to keep them from stepping up their attempts and the other half to keep their own diplomacy skills at their peak. This isn't to say the two haven't had their battles, but compared to any other faction these conflicts are often brief shows of force rather than full fledged warfare. The Reasonable Marine's dealings with the Tau do come at a price, often earning them a black mark against them in Imperial Chapters or Regiments in neighboring systems.

• Dark Eldar

It would seem surprising that the Reasonable Marines would employ non-lethal weaponry against many of Commoragh's kabals, but the usage here is for a different reason. The Dark Eldar are perhaps one of the only races the Chapter holds and embraces a hatred towards that would be recognizable amongst the other loyalist chapters. Here, the Reasonable Marines use their non-lethal weaponry, stealth and diplomatic skills to deprive the pirates of the thrills they seek in their realspace raids. It is not uncommon for the Reasonable Marines to swap over to lethal weaponry should the raiders prove particularly aggressive or sport a clear agenda they intend to fulfill, something even the Reasonable Marines don't mind admitting they look forward to on such occasions.

• Necrons

For the longest time the marching hordes of Necrons have been another example of shooting first and not even bothering to ask questions later in the Chapter history. However, this changed once news began cropping up that the Blood Angels (a chapter they long since held with some contempt) actually managed to ally with them to fight off Tyranids and then peacefully part afterward. Upon closer examination, it became apparent with time that many Necron forces seemed to be displaying an emergent organization- a civilization, no less. In fact, the disposition and behavior of Necron forces began to vary so wildly the chapter was forced to reevaluate the race as a whole. In fact, the chapter has found occasional allies in the Necrons. Though the Reasonable Marines are grateful for the powerful support, they also study those Necrons whom they do approach, in an effort to discern their motives (no small challenge in its own right) . They are not eager to turn on a valuable ally, but neither will they allow the Imperium to fall to Necron rule, be it through force or politics. Despite this newfound position as a sentient race with rights, in combat the Marines apply full lethal force against them. This is largely due to the Necrons unique physiology, whom seem fully incapable of registering pain, let alone truly die.

Currently the chapter has found an oddly steady relationship with several of the larger dynasties, where their techmarines (whose science is unhindered by the dogma of the Imperial cult) have collaborated with the Necrons to study potential cures for the flayer virus and the symptoms of dementia overtaking the eldest members. Already under heavy scrutiny by the Inquisition, this partnership is kept top secret even amongst the initiates of the Reasonable Marines, and even the senior officers are aware of the thin ice such an alliance skates.

• Chaos

Naturally, it doesn't take much of a genius to realize by now that the Reasonable Marines would never allow Chaos to run rampant. Chaos daemons and the Traitor Legions are treated with the same aggressive and unrelenting effort that any other true loyalist chapter would display. On rare occasions the Traitor Legions have looked the other way in the presence of the Reasonable Marines, perhaps because word spread that they know the Emperor not to be a god or figure of total adoration. Regardless, the Legions pose a grave threat and as such the Reasonable Marines will defend the Imperium accordingly.

The difference however is how the Reasonable Marines handle heresy amongst the people. Cults and rebellions are still persecuted, but with the Chapter's usual use of non-lethal force. With such members rounded up, they are put through therapy and rehabilitation in order to try and restore them to being clean citizens. Freedom of religion is something that they repeatedly bump into in terms of difficulty, however. The subject will continue to be a controversial one, but for the time being, citizens amongst Reasonable Marine Chapter worlds do not have to fear the same retribution for 'thought crimes' delivered in the rest of the Imperium.