I'm not entirely sure MYSELF how half these things are caused, since the Module System for modding is so complex.
I will probably eventually make 3 invisible "factions" of Steppe Nomads who all look the same but fight one another and (depending which one it is) the player, armies passing through, etc. When I get back to all this that is, exams are proving a bit of a bugger whilst I'm still trying to wirte a game, make 2 mods, run 2 websites, moderate an RP group... the list runneth onwards.
Welcome to Exilian, by the way; make yourself at home, and welcome to the madhouse.