Lord of Death

I tried the scenario. To reach my home castle, I need to gather troops and upgrade Haghesh – there's a pretty serious obstacle on the bridge. Question: what should I do after capturing my castle while waiting for my own troops to be built? Just wander around the cleared territory? So, it's not "difficult," but rather "tedious": enduring this empty time is really hard...
And why was it necessary to prohibit calling reinforcements and using a portal to the city?