I think romans should have human pretenders but the barbarians will have a great thematic feeling if they have wyrms, manticores, cyclops and other monsters.
Problem with adding Machaka in the south is that noone will be able to help them if they get into trouble.
Since i kinda hijacked this thread i apologise and open now a new Thread for the Barbarian Invasion game to discuss the Rules etc.. When we will have agreed to the rules i will edit the Europe map for the scenario.
I already tried it as SP and it worked quite well .