Tactics against Necromancers.

I'm not saying I'm a fan of using explosives. I just recalculated. And if you change the conditions, it can be defeated in 2 hits with the same artifacts and a pure strength of 6, meaning it's no problem at all. It's just a waste of 50 mana.
And also - to defeat them in 1 hit, you need to put them in one slot, meaning your army needs to be twice as powerful. Otherwise, if it's the other way around, the skeletons will scatter like fleas across 7 slots - then you definitely won't have enough mana.