Maybe you can build an hideout where you want,then upgrade in a fortified village,then in a castle,then in a fortified city.
and then... in the first megalopolis of calradia!
you can choose the the style of the architecture ec...
Clearly you need a mechanic to help manage the size of the place ...
The size and number of inhabitants or the improvement could depend on the renown or on your criminal level xd.
Inside you can take some recruits related to the culture of the place initially and with each upgrade you can add a new culture.
When you make the megalopolis you unlock the ability to CREATE your own culture and customize the troops of that culture.