Okay, did some reading, and I like Petrin, but as a political aim. Say, Grand duke sends a diplomatic party with the subtending option of a forceful takeover.
It'd go like this:
The party shows up, has their standard greetings dinner or whatnot, and get directly into alliance talk between Reajh/Grand duke and Ahjfeld. The hope is that things go well, and that a treaty is signed. The whole thing should have a "dire consequence if you don't cooperate" feel to it, and accordingly, if she doesn't, to some extent, or to the extent planned, the specially picked party siezes the (Fort/castle?) and keeps Petrin hostage until arrangements are met. If she does make truce, then the order is given for Mordecai occupation of the city. Nothing overly large, but like a set guard for the higher ups that double as a guiding hand for Ahjfeld. It works out that if some other people want to join in the thread in the diplomatic party, we don't have to sideline some NPCs.
That is a lot of preemptive plotting but IDEAS. So yeah. Think about it!
If that doesn't work, I'm always up for a war thread under the guise of "we don't like them, so let's kill them!". Soldiers are, after all, meant for warfare.
@visualspice