Ok, I've got a question.

What's the interaction between a Sector Lord and the Adeptus Terra within a given sector? Can he influence or control who gets what positions within the Adeptus Terra and stuff or is he at the mercy of bureacratic processes beyond the reach of outsiders?

The reason that I am asking is that I've got an idea for a campaign dealing with some Imperial politics and that includes some vicious feuding for who gets to put their man on the post of being the Sector Lord. Thus I'm wondering what kind of schemes could a Sector Lord do to hold on to power and advance his faction's position withoit causing a sector-wide civil war?

Well, potential measures would surely be blackmail, bribery, a small assassination here and there I guess... the Usual, you know.

As for the position of the Sector Governor, that's... quite a tough question. How I imagine it, the Segmentum Branch of the Admanistratum (Lord Segmentum Governor?) would decide who gets the place at the top of the sector. Of course, the Segmentum Governor does not know much about the actual sector, probably mostly about "how productive is it" and "are there any major conflicts threatening the Segmentum as a whole".

Thus, he'll have to get the advice from a council of people (probably AdMech, Ministrorum, Battlefleet, Noble Houses, Merchant Houses, Inquisitors, you name it) who will tell him "Well, that guy is useless" or "That guy is awesome and will double the tithe!".

Other then that, tradition likely also plays a big role, like who owes whom a favor, things like that.

Of course, this picture might be totally wrong, but considering the feudal nature of the Imperium that is my view on how things work... and it'd leave you lots of room for backstabbing, double-dealing and a general atmosphere of "No really, who can we trust to betray us and who can we trust to maybe betray us?"

Edit: Of course you have to keep in mind those organisations NOT directly affiliated with the Adeptus Terra (Adeptus Astartes, Adeptus Mechanicus) thus having their own Agenda.

I always thought planetary Governors were under Sector Governors and theoretically they answer to the High Lords of Terra which is an amassed group of political nobles. I'm currently experiencing almost the same thing. I actually have some High Lords of Terra who seek to undermine the Golden Throne. I know it's hitting pretty close to home but my Acolytes are pretty close to Ascension level and acquiring their Inquisitor Rosettes. So the way I always figured it to be from what I read is that through very formal meetings and power plays High Lords begin to filter down information to the Planetary Governors. I never really got into the specifics of the Calixis Sector Lord but I had an old game where the Acolytes started on Scintilla and they were going to eventually end up on Malfi.

Because of the bitter rival between the two planets I was going to assume that even the High Lords could also unwelcome any advances by the Sector Lord or place someone in a position of power that a network cablal of High Lords know about. The thing with political intrigue is that I try to find a story and have different personae's of the story with different agendas. When each High Lord creates their agenda, then the struggle for dominating the Sector Lord evolves. Even with maybe the Sector Lord infiltrating Terra and undermining the Cabal of Radical HIgh Lords.

Thanks guys. This give me some stuff to work with.