Indestructable: After the crusades you were given lands and titles. With peace assured you can relax. At least until the nothmen invaded the kingdom. After there defeat against your castle they retreated from once they came. Fate did indeed smile upon you.
This the mega happy ending
The other ending will require you to manipulate this map in the map editor. First Change the map into a siege. Then delete all signposts and place a new one amongst your farms. Delete the invasions and have as many powerful troops except horsemen in the attacking army. Finally set a huge fire 2 months into it and repeat for 3 months. The story ends this way.
The king has betrayed you and so did some of your guards. The enemy came from within. The mutinus guards set fire to everything. Surprised troops run everywhere. Gather your men and fight for your lives, For freedom.
This is the Braveheart ending. Indestructable indeed.