Reverse Devotion aura

I am making an aura that does the reverse thiung of devotion aura, its based on devotion aura but this aura gives - to armor instead of +, I am trying to make it only target enemy units but it always targets allies too, how can I make it only target enemy units?

target allowed =
Air, Ground, Enemy, Not-Self

That is allowed, but still it effects allies!

That is only allowed!, but still it affects allies too!!