Have noticed a couple of times that it doesn't seem to work very well.
For example: when attacking a 2+ defense city with one 4 str unit, the demon should take away the 2+ and the hero/medusa from the base str. As it is now the hero/medusa takes away strength before the demon has taken away city walls, making the special skill useless.
Is this how it should be?
By the way: Don't know if it is the same with catapults or that other -1 def-things.