AI Editor.
Edit the castle layout and priority settings, troop rally points and defensive weapon placement. Edit the existing AI (Add rolling logs to Edwin, or give Lady Seren a moat) or create one from scratch. This editor will do it all. And with in-game graphics used to produce the editor, you will see exactly what the castle will look like, down to the spike traps, rolling logs, gatehouses, poleturners and all the other buildings that make Stronghold 2 so great.