[Endoperez]

I have little experience, but I recall someone on this forum was using the Siege Engineer and cheap but defendable fortresses to just dig in and not yield. And even if one of their forts were to fall, the Siege Engineers would be just as good at conquering the castle back as they were in defending them.

BTW, I doubt the commander with fort def and siege boni of 25 is named Siege Engineer. I can't decide on how to write Physicist/Psychist/whatever.