You should create one evil super-powerful race that's against everyone (sort of like the Antarans in MoO2). They could be the only non-organic race, like sentient cybernetic food processors.
"Captain, long range sensors are detecing a massive fleet of incoming Cuisinart and Salad Shooter class ships!"
"On screen.... What the hell is
that thing?"
"It looks like a... like a giant blender, captain..."
"Order the retreat! Run away!"