Loki, "myth" civ of the Norse, can also play the MU warzzz (this time more a consumption war)
The key is to get more trolls fast -- the Atties heroes are so expensive that they can hardly be amassed (and they are damn weak). Enough trolls with hersirs will eventually get the upper hand in battle.
Hersir's armors are very, very important. The turning point in this saved game is the armory upgrade. IMO, if played well, Thor + Archaic dwarves + armory upgrades will also make a good MU war, although no MU will be granted.