[Ylvali]

Supply: Most units in the game require 1 or more supplies depending on their size and/or special traits(gluttony). Some units don´t eat supplies (like magigal/constructs/undead) while some eats a lot even though they don´t need to(some demons and magic summons) which is only a problem if they are mixed with units that eat.

If the units in a province needs more supplies than is provided there they will begin to starve. This lowers their morale and may lead to diseases killing your troops. AFAIK commanders never starve. Nature mages, some units and a few items produces supplies which can make the army feed itself. Necessary when fighting a war against for example LA Ermor.

A fort one commander has started building can be overtaken/continued by another as long as you do not the province in between. So the commander if your invading army can start building a fort while you are recruiting an indy commander who can overtake the construction when your leader needs to move on or build something else. You cannot get your money back once they are spent.