There are untold numbers of RTs operating in the Expanse and various Dynasties have different measures of success. Some manage to get strong and slowly decline only to re-surge recently while others just decline. Others yet manage to stay as middling RT Dynasties.

I'm concerned with the declining ones. Given that the Imperium is more or less a feudal society that means there is hierarchy. While all RTs are "equals" some are just more equal then others. For example, Armelan* whose House is in deep decline, wouldn't have the same pull as say Whitescale. (*PG 24 of LotE)

Could Whitescale hire Armelan to work under him? Maybe even force the arrangement if he bested her in combat? Apart from the obvious pride issues, do you think a RT House would get desperate enough to essentially make themselves a vassal to a larger more powerful RT House?

Which brings me to this stray thought. Lets assume Whitescale kills Armelan in a fight. She's the last of her line. What happens to the Warrant? Does Whitescale get it by right of combat? Eat it to gain its powers? Give it to a cousin founding a cadet branch of the Whitescale Dynasty? Which brings us back to would that cadet branch be essentially a vassal to the main branch?

Warrants are very complicated things. Not all are hereditary, especially the newer ones which are riddled with all sorts of clauses. You have to help the Ecclesiarchy when they ask. You always have to support the Imperial Navy. You can't bombard planets occupied by Imperial citizens. It just goes on and on.

But till, Warrants are pretty rare things. You can install someone who claims to be of that line and have them as vassals.

Rogue Traders will work where there's profit. The Saul Dynasty has a fleet of trade ships that probably intersect with many other dynasties' holdings. He may put himself in a subservient role hauling cargo, but he's reaping the profit off many and consequently has a large amount of influence (and wealthy).

There are a few Rogue Traders with dwindling wealth and influence who would work for others as well.

Everyone's equal. Some are more equal than others is all.

Warrants of Trade also have specific clauses to determine secession. Some of them say "Whosoever holds this Warrant has all the rights of the Rogue Trader", which are extremely valuable and well-guarded. Some might say "Whomsoever is appointed by the Council of Sinophia following the passing of the current Rogue Trader shall be the next bearer". Some might refer to the eldest son. Some may say whomsoever shouts "FIRST!" at the Rogue Trader's funeral can get the Warrant. It's all pretty variable.

However just because you gain someone's Warrant of Trade doesn't necessarily mean you gain their stuff. My players killed a Rogue Trader, and then just expected his fleet to instantly switch sides. They did not. They merely opened fire on their former captain's vessel in a devastating barrage, nearly killing my players. Although maybe some Warrants do work that way! Again, no one knows.

Marwynn is also right about the owing favours and requirements of the Warrant, which is the most likely scenario where you would see an alliance. In general, the older a Warrant is the more powerful and the less restrictive it will be. However because of all the different powers it might have, it would be a foolish Rogue Trader who is upfront about all the abilities his Warrant of Trade gets him.

From my reading I have gathered that Warrants are near unique unto themselves, which each Warrant being more or less handcrafted. And that older Warrants are better in that they tend to have fewer restrictions. One from saw M30-31 might just say go forth and expand the Imperium and its signed by the Emperor himself. Lots of leeway there. While another might have come out of the Calaxis Sector and be restricted to just the Koronus Expanse with a huge list of caveats and addendums.

That said most Warrants I've read about seem to be hereditary, though primogenitor or even direct descent doesn't always seem to be the case. Chorda for example was the 3rd kid of 6 and she is the one holding the Warrant. In any case going back to my OP, assuming a Warrant is hereditary and the last of the line is killed off, I assume the victor could make a case to gain the possession. That or maybe the property reverts to the state/planet/Imperium? However in the case of it being a "Whoever hold this" Warrant, I could see Whitescale giving the Warrant to someone with the conditions that they are basically working for Whitescale. Mechanics wise I would assume this would mean Whitescale got a piece of any PF the new RT made.

I do agree though that just cause the RT is dead doesn't mean all of their things will quietly transfer over. Some will take the death of their RT personally and try to exact vengeance. Then again, maybe family X has been working for Warrant Y for many many years and are loyal to the Warrant as it affords them a comfy life doing whatever. So long as their status doesn't change maybe those elements go over quietly. New flag, new boss, same old job.

Also I will point out that you guys have given me something to pursue with my GM now. In our first adventure Into the Maw we sort of killed Haradak Fel. And we're pretty sure he's dead as the plasma cores went off on his ship. And we looted said ship and found no survivors. So I'm going to have to see what becomes of his Warrant. If I can get it I'll see about getting a RT to work under me.

Edit: As a word I used got censored so I swapped it out for a less sensational word.

It's also worth considering how the various assets are tied into a dynasty.

They may, for example, be contractors on indefinite retainer; the ships may be the property of individual captains who have themselves sworn allegiance, to the man or the line; the ships may be directly owned by the Rogue Trader, and crewed by his men, or by contractors, or slaves; the Dynasty may be organised as a Joint Stock corporation, with the Rogue Trader holding the majority of shares.

All of these would deal with a succession crisis in a different manner (although the odds are they'd all react initially by shooting at the guys who killed their boss).

In the case of a Warrant that was issued with a hereditary succession clause tied to a particular familial line, upon the death of one bearer it should (technically) revert to the nearest person by degree of consanguinity (assuming there are no problems with competence, etc.): this could mean going back generations, leaps through the salic line, and wind up with the next "heir" being a seventh cousin-in-law, nine times removed. However, at that point, it's far more likely that the Dynasty, or whatever body is called upon to ratify a succession, is just going to declare the whole thing too silly and declare the line extinct.

When that happens, the Warrant itself should probably be escheat to the Throne, and all entailed properties with it (which is where figuring out how the various assets are tied to the Dynasty is useful. Also, the terms of the late Rogue Trader's will, once probated). Depending on the age and provenance of the Warrant, it may be sought after by the Orders Pronatus of the Ecclesiarchy as a relic, or by other organisations for its historical significance (this has happened even when there has been a viable heir to the Dynasty- if the Emperor signed a piece of paper, people wants it*). In any case, the entailed property, having reverted to the Imperium, would then be under the control of the Administratum for disbursement- they may not feel like re-issuing the Warrant itself, but they could probably be persuaded to issue (more limited) Charters and Letters of Marque to the ships involved, and/or selling them off to interested parties.

*It's worth looking at the novel Legacy , by Matthew Farrer, as it deals with the Succession of the Phrax dynasty.