In multiplayer campaign Orion controls the Oak of Ages, leaving Durthu without those useful bonuses. I thought, that I could manage without them, but in reality it's overcomplicated.
On "Very Hard" difficulty you suffer a -8 public ordr penalty, which is comprised of difficulty and tax modifiers. You can't get rid of them - there is no tax slider in this game.
To combat this negative effect, you a have a single building chain, which will provide +3 maximum, and a tech, which grants +3 public order factionwide. Offices don't have any effect on public order. Therefore, you are stuck with -2 public order in settlements.
The Oak of Ages seems to be the main thing, that maintains public order for a player, so how is Durthu supposed keep rebelions at bay? Either I have overlooked something or the devs din't pay attention to it.