Armageddon's Magic – it really shocked me.

If this spell is cast by the artifact's wielder, it affects all units on the battlefield. If it's cast by an opponent, it affects all enemy units and only those of their own troops that would be affected even without the Sphere.

The catch is that he could cast Armageddon with the exact same disastrous result for himself! :D That's why I clarified the point... And you're right about everything else... :D