Well, since you asked!

Are they going to be regents? Actually, that shouldn't matter too much;
you can take this either way. Here is the thread of adventures to what
I did IMC in this part of the world:

1) If someone is going to replace Marlae, have her assassinated. Make
it look like the (PC) heir was responsible or somewhat involved (even
better the latter). Throw suspicion onto this character - but make the
PC priest discover clues to the contrary and endear him to the future
landed regent (PC). If not, just have an *attempted* assasination, and
have Marlae endebted to this priest (heck this is a good reason to allow
the building of that level 1 temple to Ruornil in Caercas! I did, and it
was worth it IMO). Priest saves her bacon and is rewarded with regency.

2) Then, have things cool down. Do a little court intrigue and the
like; make all the players think step one was successfully concluded, or
just a freak/random occurence. Lie about and obfuscate facts, allay PC
suspiscions. Make them cozy in their newfound security. Good PCs,
though, ought to be paranoid, and then you know your doing your job
right. But this works to the DMs advantage ... :) This next adventure
will focus on the PCs trying to clear the provincial regents name (or at
least, take attention away from them. IMC, the new PC really DID
assassinate his sister ... boy, are my PCs psychotic or what! Mind you,
I was the one who suggested it ... MWUHAHAHAAHAHAAA!!! Played right
into my campaign plot!!!) :)

3) The new provincial regent, now 'secure' on his or her new throne,
finds that there is more to being a regent than just honey and
sweetcakes. Gosh, they have to attend an important state function. May
I suggest the Intro adventure in the back of Ruins of Empire? Have a
wedding of an important noble (I suggest Bellam, like portrayed in that
adventure). Otherwise, make it the noble of Ghoried. Now, of course,
The Iron Duke has this 'noble' on payroll. Hope you know what I mean.
Time to weaken Roesone's power base, hmmm? All to easy ... Hopefully,
the PCs will escape relatively unscathed, and discover a couple of more
new clues in your unfolding plotline. Have the new gopher boy of
Roesone, the PC priest, be the one to tie the knot; put him at the
center of all the opposing forces.

4) Lull them into a false sense of security again. I suggest
introducing events and intrigue on a larger domain scale, ones that
advance your larger campaign goals. Send an envoy from Medoere
(remember the priestly envoy in the intro of the Roesone sourcebook from
Medoere? Did the new Roesone regent forget about that? Well, here is a
'friendly' reminder). Boy, the PC priest is in real trouble now, since
he was the one who was supposed to gain the audience from the regent,
right? Introduce threats (or overtures of peace) from Diemed. Isn't
the Duchess of Tuornen a second cousin? Marriage bells? The High
Prefect of IHH concerned that mister bookworm priest of Ruornill is
weaseling in on 'his' claim to be Chief Religious council to the regent
of Roesone. Whatever you do, take the focus AWAY from The Iron Duke and
his flunkies (hopefully, in step three you DIDN'T give away that Ghoere
was involved. Circumstantial evidence is fine, but don't give away
damning evidence, unless you feel you can handle it).

5) Keep their attention focused elsewhere for now, once again. Isn't
there a new awnsheghlien in Medoere (btw, if you like, I'll post this
here for you - I called him 'The Swamp Thing'). PC priest's parents are
threated back in his home of Medoere! Trouble with fhormoriens down in
Abbatuor? Pirates from Mieres? A cult of slave traders in Aerenwe (