I have been brainstorming some mechanics for transitioning Dark Heresy characters into the Rogue Trader classes (I also posted this in the Rogue trader GM board under the DH- RT thread).

Essentially at 5000xp, the characters could choose a rogue traders class (limitations listed below) to expand into. It would work in a similar way to the alternate class levels in the Inquisitor's Handbook. In fact characters can still gain skills from their former levels. However attribute increases will be restricts. So say if a guardsman increased his BS by +10%, his BS in the new class is treated as if the BS is at +10%. Also once the character transitions to the new class, attribute purchases are based off that new class.

There are limitations on class transitions however.

The Astropath and the Navigator cannot be transitioned into.

Any characters with the noble origin path, and/or any character which has recieved a warrent of trade may enter the Rogue Trader class

Guardsmen, Arbites, assassins, scum, and Sororitus characters may enter the Arch militant class

Tech-Priest, or forge-world born adepts may enter the Explorator class

Clerics and Sororitus characters may enter the Missionary class

Adepts, arbites, assassins, scum, and sanctioned psykers may enter the Seneschal class

Adepts, Guardsmen, and scum may enter the Void Master class.

This was just an initial thought on how to transition to the rogue trader classes. If this is used the usual attribute generation, and background generation from the rogue trader book are not used.

Salcor

Salcor said:

Thing is, do you really need to? a 5,000xp Dark Heresy character does sit on about equal terms with as starting Rogue Trader character - the biggest hurdle is really the fact that the DH career paths stop at a point equivalent to the middle of rank 4 for Rogue Trader career paths. Further, Dark Heresy covers character concepts not present in Rogue Trader, and vice versa, meaning that there's plenty of room for characters from both versions of the system in a given game. Certainly, that's what I'm planning on doing.

I broadly concur. From around the 3000 mark I'd permit DH characters to the RT careers as 'alternate' careers as outlined above, provided they've been spending oodles of time on starships, around starships, are about to or they've been heavily involved in commercial-y stuff.

That said, N0-1's spot on too; there's no overarching or really specific reason, especially not with appropriate elite advances, that both DH and RT characters of similar level shouldn't be compatible in a game. Still, overlap is interesting too.

I completely agree that starting level Rogue Trader Characters and 5000xp Dark Heresy characters are on the same level. This transition house rule was set up for my group because I was going to run them through Tattered Fates with one of them being a scion of Haarlock. Since the rest of the campaign is behind I was going to have it end with that character recieving the warrent of trade for one of the haarlocks (since it seems like they had a pretty large fleet). Thus I was going to give him the option to transition to the Rogue Trader class (he was a noble imperial guardsman). I figured I should give the others that option to transition to RT classes as well.

Salcor

Not too bad. My only major problems are:
1. Sororitas aren't priests in the standard sense and as such should not be allowed to enter the Missionary class (most especially the orders Militant).

2. The advance scheme is one level higher and I feel some provision should be made for this (I'd suggest adding an extra level of characteristic advance to DH)

3. Consider that you need a pretty powerful pretext for transferring acolytes from an inquisitor's retinue to the service of a rogue trader (they don't have jurisdiction). I'd have to say that there are few reasons for this to happen. There are possibilities: the rogue trader is a comrade of the inquisitor and requests some skilled assistance, or during a mission the inquisitor is killed/disappears and the rogue trader 'inherits' the acolytes, or adopts them.

As a final note, have you considered that an inquisitor has the authority to requisition any aid he sees fit from the Adepta, or any other Imperial institution? Why not have him/her requisition a ship, or even an entire fleet? You could even have him/her (a Lord Inquisitor) requisition a rogue trader fleet (of course this could be sticky as it's likely to upset the rogue trader).