I'm trying to run my first RT campaign for some players. I'm wanting to add some depth in the story and create an Astartes contact. My question is, what really happens to an Astartes who has broken his Oath of Moment? I feel ridiculous for not already knowing…I might even know the answer and just not remember.

Oath of moment is something introduced in the Horus Heresy novels, it isn't something touched upon elsewhere to any real degree. Now that 10 thousand years have passed and many chapters have greatly diverged from the legions they were originally part of i'd imagine a lot of them either don't make such oats or make them in a very different way. 

The Iron Snakes chapter for example are from a watery death world. Their chapter structure has each squad accompanied by an Apothecary who has a vial of water from their home world. Before important missions each member of the squad is annointed with the water.

Black templars on the other hand are fairly close to their original Legion in so far as they are constantly 'crusading'. This means that oaths are taken all over the place by their members and its not unusual for a Black Templar to go into battle adorned with dozens of purity seals inscribed with the oaths he has taken.

Ultimatel its up to you - there is no hard and fast rule for it, though i suggest looking in the Deathwatch core rulebook as it has a selection of oaths that the players can make before each mission.

Thank you so much for your answer. That helps me a lot. I always knew them simply as "purity seals" until I read the Horus Heresy novels. I was just not sure if there was a specific punishment for breaking it. So if I were to introduce a banished NPC or group of NPC Astartes all left to a planet with horrible conditions and no civilisation…Do you think that would be an acceptable idea? Or do you believe the punishment would be less or more severe?

ThunderBear said:

One does not abandon an Astartes as they are simply too rare. if they do somethin treasonous, then they are killed. Otherwise, they are simply directed at the enemy again until they atone or die trying. Some are given to the Deathwatch, especially if they are disgraced within their own Chapter but highly skilled.

I figured as much. I'm trying to create an Astartes and figured an easy way would be to make him banished. I'm now thinking of having him flee to avoid death. The reasoning behind it is wanting this NPC to provide work and knowledge that will tie into the plot of why he isn't in any unit in the first place. If the Imperium or Inquisition are actively searching for him, that could also add in some suspense and/or stress.

Actually, there is a way of getting a sole Astartes because he's upholding an oath, not because he has broken one. This is called the Death Oath, and I think that the most notable character that received one is Uriel Ventris (and he's one of the two Ultramarines that I like). What is a Death Oath? It's quite simple: an Astartes is charged with a suicidal mission, stripped of all honour and ranks and virtually cast out of his Chapter. If he ever succeeds, he's again in the Chapter.

But, generally, he had to fail earlier in something important and be something other than a "cannon fodder" Astartes (I'd say at least a sargeant), because he's seeking redemption.

While upholding the Death Oath the Astartes cannot count other Space Marines as his allies, he cannot resuply in their facilities etc. He's just a lone superhuman bent on doing the nearly impossible.

I like all the replies so far. But what about just having the lone marine need a ride from the Trader to rejoin his chapter? Or alternately he was left behind (possibly assumed dead) by his chapter that set off on a crusade and is hitching a ride on the Traders ship until he figures out what to docoe where to go next. 

The "presumed dead" angle is a tricky one, because the Chapter would attempt to recover his geneseed - with the Apothecary obviously discovering that the guy is still alive. It depends on the circumstances, though. If it was enemy territory and his brethren decided a recovery mission would be too dangerous … alternatively, he could be the sole survivor of an entire strike force that was wiped out, almost having joined his Brother-Marines in death (but having recovered over the course of several lonesome weeks thanks to his superhuman physique), his Chapter not even knowing what went wrong and simply having lost contact with his Company.

I agree with Behir in that the Oath would be the most convenient, easiest, and most interesting/promising way to include a single Astartes or a small group of them, though. :)

Cryhavok said:

I like this angle quite a bit. Lots of potential hooks for GM. 

But also as far as I can tell, not all gene seed is recovered, and in several novels a battle brother is given up for dead only to return later in some dramatic fassion. So any GM that tries to claim the fluff says all gene seed is always recovered is being a bit to narrow in my opinion. 

DigitalRedneck said:

A Chapter's geneseed is its life, and any loss in geneseed lowers the Chapter's ability to replace casualties. A number of Chapters were disabled or went into extinction only because they lost too much of their geneseed. This is also why the geneseed storage is the single-most protected place within a fortress-monastery … and on Armageddon, Inquisitorial black-ops snipers have specifically targeted Apothecaries just to prevent them from reclaiming the geneseed of the fallen.

So when a novel author crafts his story around a Chapter's casual disregard for its fallen brethren .. then I'm gonna say that this author is "a bit narrow". ;)

But, of course the above is just as per GW's material. There may be other interpretations of the geneseed's importance, depending on the source one would look at.

That being said, I kind of like the disgraced apothecary idea I just posted more as it adds more dimensions to the situation than the hero does in my opinion.

I am not sure we have the same Deathwatch core book? In mine it does not say that marines always deploy with a apothecary who must collect all the gene seed from the fallen or face banishment and disgrace. It does say stuff like recovering the chapters precious gene seed will be aattempted if at all possible. But I see no indication that an apothecary is ever told "don't come back without all the gene seeds or else!". 

Cryhavok said:

This is my favorite idea because it includes so many plot hooks. Not only must he return, but all kinds of people would kill to get gene seed! Then there is the result of whatever mission the apothecary was on at the time. Great way to get some bad guys chasing the PCs..  Oh, the list is endless. 

Lynata said:

I don't recall accusing any Author of casually dismissing the importance of gene seed. Not in any novel I have read so far have I seen this. More have I ever read a novel about marines where every fallen brothers seed has been recovered, either. (that I can recall off hand. And I think I've read only five or six books with SM as the focus… So I don't know everything!! Lol)