Hello, I am looking for some insight into a campaign where two major regions separate the continent, which is divided by a desert. The PCs travel to both sides and complete missions and become friendly towards both sides ... but what about when it is unveiled they want to wage war on each other? Both sides see the PCs at this point as heroes ... how would it be if a continental war was began between two factions (north vs south)?

So, presuming both want their services (and both sides are adversarial), both would likely try to identify the party's buttons, and then push them. What are their motivations? What are they vulnerable to? Fear? Hate? Country? Family? Authority? Shame? Glory? Friends? Money? The afterlife? Pride? Figure that out and then decide how each side will attempt to manipulate those motivations.

- In short it sounds quite complicated campaign structure if players dont clearly help one faction.

- How about option that players are able to choose one side during campaign?

- Is it important goal that the other faction does not know that players are helping the other side?

In my current project I have two factions and players can join one faction or stay neutral: http://homebrewery.naturalcrit.com/share/By3s5Uqqf