As it stands I am completely stuck on two separate playthroughs because I cannot for the life of me get enough XP to reach a high enough level to be able to progress in the fort.

On my first playthrough I have 3 characters (I killed Sebille) - main character lvl 3, others lvl 2.

My second playthrough has 4 characters, all party members lvl 2.

In both cases I am stuck with no further ways to get XP that I can find. I must be missing something major.