"Weak demons"??

Losses in battles against spellcasters and archers are an unavoidable evil for demons. About 5 percent of units are lost. But there's nothing you can do about it. The battle tactic is the same: choose a target in the form of a large stack of your units (demons/greater demons/fire demons are best for this), divide them into 5-6 stacks of imps, and then actively use the "Mark" spell and demons to finish off the remaining neutrals. Therefore, the "Machine" skill is indeed useful, but only for a secondary hero. It's not worth using it for the main hero: in the final stages, this skill becomes ineffective within the first round. So, there's no point in taking it for the main hero: we lose at least 5 levels. Temptresses usually go after archers or spellcasters. Therefore, we use the same tactic with a large stack. Archers and spellcasters in 90 percent of cases attack units with the highest total health first. With upgraded "Machine" skill, you can generally manage to partially resurrect a lost stack, for example, Lords (more health, less damage relative to health units from attacks). Mass Dispel is good, but nothing beats Berserk and Subdue against strong neutrals...