Armageddon's Blade is a good item, but recently I attacked a Tower with Necropolis units.
And the hero had Armageddon's Blade. I had to load a save and use the Sphere of Inhibition. And they all fell! And I had no losses! :-)
I was wearing Cursed Armor and the King of the Dead's Cloak.
As it turned out later, after the battle, the enemy had Anti-Magic Aura, but with Armageddon's Blade.
By the way, I also like this set.

Tip: don't change the Sphere at the end of the week for a bonus to units ;-)