For making any unit in a region invulnerable
Events
Map initialization or Elapsed Game Time 0.01 secs (didn't test if map init works, but it should)
Conditions
Actions
Unit Group - Pick every unit in (Units in [Any Region]) and do (Unit - Make (Picked unit) Invulnerable)
For making specific unit in region invulnerable (e.g. peasants)
btw its units in region matching condition
Events
Map initialization or Elapsed Game Time 0.01 secs (didn't test if map init works, but it should)
Conditions
Actions
Unit Group - Pick every unit in (Units in [Any Region]((Unit-type of (Picked unit)) Equal to Peasant)) and do (Unit - Make (Picked unit) Invulnerable)