Round table

A question about a situation, SoD version: I attacked a hero with Phoenixes using the Orb of Vulnerability. In the end, he wiped everyone out with Armageddon, but it didn't affect the Phoenixes; in PhysMig it says - Armageddon. If this spell is cast by the artifact holder, then it hits everyone. If it's cast by their opponent, then it hits all enemies and only those of its own troops that would be hit even without the Sphere. So, as I understand it, regardless of whether I have the sphere or not, Phoenixes are immune to Armageddon??? And how does this work in VT???