This total overhaul of Rome:Total War is based upon the Second World War. It contains historical battle locations on different fronts.
So these are the playable factions in the new European Campaign - all the factions like Poland, Greece, Yugoslavia, Belgium, Norway, Denmark, Netherlands and Sweden etc will be rebels on the map - because we aren't releasing another upload - this campaign is still a part of the main mod and as such has the same factions.
This means that the new campaign won't have any new factions, but instead will have lots of rebel territory in those areas where defeated factions would be.
Also, the main factions will probably have some rebel areas in their territory as well to slow down their advance and aid the smaller factions. Historical accuracy isn't the main focus of this campaign, it's more of a sandbox.