DarthStarkiller to be honest i expected Yugoslavia in JFD'S WW2 civs with Tito as leader and Partisan as UU and some building probabbly for second unique component. For Peter I as i know from history probabby is unique artillery and GG or Great war infantry. Because Serbia stoped much larger AU army i will give some boost on fighting in friendly land and not like Ethiopia (if had more cities bonus) bonus on fighting with larger army.Also from history Serbia retreat true North Albania to Greece,then coming back with French troops. I think Pouakai can think something interesting for Serbia WW1 UA. For decisions i really don't have idea.