I suppose that, RbAW, Astartes are not so common in the Expanse, but I wonder, if your party wanted to get in good with some, how might they do something for the Angels of Death that would actually get them to take note? Some few Rogue Trader warrants have fine print that can associate them with an Astartes Chapter, and you with them, but how might you earn this. I'm honestly not looking for an excuse to have a unit of Storm Wardens, or Deathwatch, frequently aboard my ship, but say one of my Rogue Trader characters had a "signature item", in this case one that tells people who they are, more than what it means in Deathwatch, and that it's something not typically available through "mundane" means. How might the Space Marines be inspired to give you such a gift.

As an example, my RT NPC Aedan Qel-Drake wears a long jacket that looks like salamander hide, and for right now is, and even gives him a bit of the bonus that mantle does. Were I to stick with that, and not say "a resembling, but legally-distinct from Nocturne's Salamanders dragon lives on a Death World in the Expanse", how might characters in the Koronus Expanse encounter Space Marines, and do what sort of service to be rewarded, beyond "it's what was expected of you." With so many dragon themes, I like Aedan having met the Salamanders, and having received some of the hide of a Salamander, to turn into a coat (Astartes I think just wear it like a cloak), but even if the Mantle weren't normally restricted to heroes of the Chapter, I don't know what a Koronus RT might do for a Space Marine that the Space Marine wouldn't just leave, and continue their business. Thanks.

Possible acts/actions include:

Finding/recovering an item of major significance to the Chapter (or parent Chapter/Legion).

Perhaps it's something an ancestor of his did and he inherited the cloak/coat/item, and the heirs of said ancestor were permitted to wear it. Probably the best option, tbh. The exact actions of the Ancestor could even be lost to the living memory of the RT's House, but would doubtless be in the House Archives (somewhere), and of course, depending on how long ago this ancestor lived, there may even be yet living Astartes who were personally acquainted with the ancestor.

Finding/recovering the remains of Astartes who were lost, most likely on a space hulk expedition or captured by Dark Eldar, or were on a ship lost in the Warp. Or it's remotely possibly that there was one or more survivors who were also found/recovered.

Finding/eliminating an entity or organization that had particularly offended or otherwise drawn the ire of the Chapter. Likely someone who had transgressed against the Chapter/the Chapter's Honor in some noteworthy way.

Major acts of heroism, doing something that impressed Astartes observers. What this entails would vary by the Chapter and their mindset/outlook/etc.

Also, since he's a Rogue Trader, as long as he came by it legitimately, it's unlikely that he's going to stick by one version of events, and will likely (quietly) encourage the telling of tall tales and wild rumors about what he did to earn it.

One possibility I'd thought up for a similar situation was the following. Rogue Trader is out in the expanse doing his thing. Runs into a SM ship loosing a fight with some superior enemy (say a couple of chaos ships vs the one SM ship). Rogue Trader decides to jump into the risky fight and help the SM against the foes of man. Maybe they win, maybe they help them escape, maybe they rescue the survivors, whatever. Either way they've shown their valor against a ostensibly superior enemy, gone out of their way to fight the enemies of man, and rescued the chapter's warriors from potential disaster. Probably good enough to "get a good word in" if nothing else. Take it a step further and offer to escort the damaged ship back to imperial space or help them complete their mission, or otherwise go out of their way to lend a hand, and you could probably make good friends with the chapter.

in the last RT game I GMed, the players did the following:

(not by goal, but in 4 various random encounters)

1. return recovered lost items as mentioned above #1 by javcs

2. relay data back to SM chapter on a location of a downed SM ship.

3. trade starchart & xeno location data with a passing SM barge's navigator.

with an implied "scratch each other's backs" later on as regards

disposition of said xenos

4. ensure the SMs of refuelling and resupply rights at their Svard base.

this allowed the RT to purchase Peer:Astartes

Edit:

Forgot to mention that on 1-2-4 above the RT did these gratis for the SM,

no trade implied or asked. And item 3 was the idea "we can get them together,

you get the glory and I get the loot or worlds."

It was the Storm Ravens and Gold Legion, both SM chapters that fool around

in Koronus.

My issue with the above is one little thing; the setting does an okay job of trying to say that the Rogue Traders of this game predominantly work in the Calixis Sector, and the Koronus Expanse, and that these areas are rarely visited by Space Marines of any loyalist Chapter. What would Space Marines, or their ship, be doing out beyond the Imperium's edge, where only CSM frequnetly go? I don't want it to seem that the Salamanders spend a lot of time in the Expanse, but something had to bring a group of them out there. If the Reach was a more known of spot, and the occasional Strike Cruiser could stop by, and benefit from RT allies enroute to the Jericho Meat Grinder, that might work, but I'd have to come up with a better reason than "I'm a snowflake who wrote that my RT has, effectively, a lesser Salamander Mantle, and so I need them to stop by and grant him one", even if that is sort of what I am doing. Both of my RTs seem to get some standing among the Space Marines, but the one is from ages back, before a millennial gap in the Warrant's operation, and his own interaction with the Astartes is amicable, but very slight, as he's actually been in the Reach, and met some Raven Guard, while this one doesn't have the same level of ties, but shown value, to receive such a reward from the Salamanders. I guess I just like having the Space Marines show some favor to other warriors, in games where they aren't the stars, but without the whole "I have a group of Astartes semi-permanently aboard my ship ;)" cheese that would be cool, but hard to manage in this day of Imperium. I'll reread the above, and anything else that gets posted, and see if I can hammer out anything believable more than "convenient for me." Thank you all very much.

Also, I'm not saying that the above isn't believable, but that I need to write it in a way for my character where it STILL is believable, and not just "plot exposition" to get a cool maguffin. Weird that the Corsair's Kiss had an easier, if unbelievable story, but running into Eldar pirates seems more plausible than passing Salamanders.

Salamanders do seem like a stretch, but you could easily have some Carcharodons out there in the midst of the darkness. That's their entire mission most of the time, as far as I've been able to read up: go out there and stomp whatever seems like it might need stomping. Just a thought.

For what it's worth, I'm wrestling with the same thing in my campaign at the moment. It's a bit of a different situation, because the Expanse our game is set in is the site of a failed crusade. They found where a company of Astartes made their last stand, and have decided to set out on a pilgrimage to find the Chapter and return the armour, weapons, and bodies to them so they can be restored to their rightful place. I feel like that deserves some kind of reward, but darned if I can think of anything cool.

I run my games in a home brew setting that ties in with the events of my other games in other 40k systems. In this area there are two chapters operating, one that as based in the area and another which is only present in part as one of their fortress monasteries moves through.

I decided that the stationary chapter would be younger while also being scary dogmatic monastic Templars quite happy to burn whole worlds if they think they are disloyal or "Too Weak To Serve The Blessed Emperor!" (I have always portrayed them speaking entirely in Caps Lock). They are not nice people being insane honour before sanity types and regarding any weakness as being disloyalty (up to and including wearing camouflage or seeking cover (after all "If You Have Faith The Blessed Emperor Will Protect You!)). They are also called the Eagle Masters and have no humour about that at all, they are a font of memes for my groups. One rogue trader group managed to get in good with them after they got into an epic war with some Orks over an asteroid belt (that had no useful resources and was not strategically important in any way) when after several years of wasteful fighting they stood victorious they were asked by an imperial navy admiral why they dragged so many imperial forces into fighting the Orks the Rogue Trader responded with "Because they were there!" which the attending Eagle Masters regarded as being a fantastic response declaring the Rogue Trader a "Worthy Servant Of The Blessed Emperor!".

The other chapter is the Guardians of Light, they are older and much more level headed and reasonable, they travel through space on their ancient fortress monastery and try to do as much good as they can (unlike the Eagle Masters they actually care about the well being of people shock horror) but their main obsession is the recovery of ancient technology and knowledge. A couple of the Rogue Trader groups have gotten in with them, one group basically having them as a trading partner where they exchange ancient pieces of tech and knowledge periodically, through which they have managed to get some very useful info and some interesting pieces of equipment. This has also often led to the chapter giving them info to go and get something the chapter wants which they then trade for. The other group has by on more then one occasion coming to the aid of chapter forces and through acquiring some interesting archeotech for the chapter have slowly evolved into being agents of the chapter, able to call on chapter aid while also acting as a deniable asset for the chapter (useful as the chapter is looked upon with some suspicion by the authorities.

Basically I've tried to build a relationship between the chapters and their rogue trader allies rather then having it be a more one off thing.

Like others have said I think it really comes down to finding some relic a chapter or the deathwatch finds deeply important and getting them to actullay admit they owe you a solid, at which point you can maybe call in that one and only solid in a specific situation in which you're not doing something too rediculously shady or where the shady thing you're doing falls in line with the particular form of subversive behavior the Astartes are usually up to.

I think the important thing to understand about the Astartes is that from the perspective of a mortal agent of the Imperium their actions are going to be fairly inscrutable, each chapter has an eye on the long plan it wishes to see though. Meanshile the Deathwatch lives for an even longer and more inscrutable plan than that. These are guys who have a very clear vision of what they think The Imperium should be moving towards whether The Imperium agrees or not and they only get away with it because they are tougher, stronger, smarter, longer living, less distracted, purer andjust generally more bloody minded than anyone else in authority despite the fact that they're forced into the eternal role of errend boy and hitman.

Well, "finding the relic" is fine, except than I have to ham-fist what an important Astartes relic, preferably a Salamander one, is doing in the Expanse. Again, I will needlessly whine that, RAW, the players are expected to be stuck in that region, even with said "region" being stupidly vast, and Salamanders don't have a history of doing stuff there. I could have a Salamander ship poking near the Halo Stars, looking for SOMETHING, and then get attacked by SOMEONE, whom the Exalted Wyrm might help defeat. On the other hand, maybe I will have the item be from one of the RT's ancestors, and even the dynasty might not entirely remember how they gained it. While I like the character doing it himself (a braggart needs bragging rights, even if Space Marines don't bring pretty women with them for him to hit on, and lose cred with the Astartes), the Salamanders might not be so impressed with the kind of goof he sometimes is, and at his young age, he probably shouldn't ALREADY be rubbing shoulders with Space Marine heroes. Maybe his great-grandfather was poking around the Reach, and got it, then came to the Expanse, and the dynasty grew from there, or some other, closer, less "we'll kill you if you know of this!" sector of space where the Salamanders actually do stuff. Sort of a shame Nocturne is on the other side of existence from the Koronus Expanse...

Again, thanks everyone for your thoughts, and any more, if you have them.

Well, "finding the relic" is fine, except than I have to ham-fist what an important Astartes relic, preferably a Salamander one, is doing in the Expanse. Again, I will needlessly whine that, RAW, the players are expected to be stuck in that region, even with said "region" being stupidly vast, and Salamanders don't have a history of doing stuff there. I could have a Salamander ship poking near the Halo Stars, looking for SOMETHING, and then get attacked by SOMEONE, whom the Exalted Wyrm might help defeat. On the other hand, maybe I will have the item be from one of the RT's ancestors, and even the dynasty might not entirely remember how they gained it. While I like the character doing it himself (a braggart needs bragging rights, even if Space Marines don't bring pretty women with them for him to hit on, and lose cred with the Astartes), the Salamanders might not be so impressed with the kind of goof he sometimes is, and at his young age, he probably shouldn't ALREADY be rubbing shoulders with Space Marine heroes. Maybe his great-grandfather was poking around the Reach, and got it, then came to the Expanse, and the dynasty grew from there, or some other, closer, less "we'll kill you if you know of this!" sector of space where the Salamanders actually do stuff. Sort of a shame Nocturne is on the other side of existence from the Koronus Expanse...

Again, thanks everyone for your thoughts, and any more, if you have them.

If the relic in question was being transported aboard a ship that was lost in the Warp it could easily have wound up anywhere (and possibly any when as well). It doesn't need to have been recently lost either. For that matter, depending on what it is, it could have been taken as a trophy by someone, and ultimately came to the region of space where it was recovered - this likely works best with something that's been lost for a longer period of time.

And if you find a lost Space Marine relic/ship whatever, and send word to the Chapter (or a familial Chapter) that it belonged to before it was lost, it doesn't matter where it is, they will dispatch a fast ship and an honor guard/recovery team for it as soon as the message reaches them. For that matter, it's not unlikely that other Chapters would be willing to assist the relaying of the message/transfer of the responding forces.

I could accept that. Even with efficient warp travel, you can't always be certain how, where, and when you will exit, and when things actually go wrong, especially catastrophically so, one could say pretty much anything. I might actually be able to make this work. Thanks.