How do I use Armageddon's Blade?

I myself experienced the Armageddon spell from Ogre, playing as Ravenna in a duel... The opponent only had golems left, and he was hitting me with Armageddon (golems are resurrected)... It was terrible.

Added after 50 seconds
By the way, you can create a rune of elemental immunity for the Dwarves and blast away with Armageddon!