At the beginning of the game, I saw that my relation with the mountain and the forest bandits was -30.
I wanna know: Can I increase the relation with the bandits or can I only decrease my relation with them?
You can bribe them and get them up to about -1, they reset after a period of time, or at a set time to -30. The bribery option is only open if they initiate contact and you relations are above a certain point (-90?, -99?).
what self respecting lord may be friends with the bandits you ask ? we all know all of those cowards (other than us) are in league with the bandits ! otherwise they'd all be dead
Nobody really wants to have bandit friends. Nobody. It's like having a unwanted family "friend" who is always drunk at parties and behaving badly. Worse than you but embarrassing. And it demands money to keep the realtionship. Eventually you just unsheath the blade...