Speaking purely realistically, the rebuilding from this sort of calamity would probably take up to ten thousand years + due to the population issue all things considered. Maybe shorter

Of course, this is an RP, total realism isn't desirable. 
Perhaps if there were other communities which weren't other players that could be conquered. To introduce some needed diversity. Not that the Ogres need that much, they're sorta at a point of no return aren't they