the armor on it takes over your armor.
That is, with it active, whatever your armor is doesnt matter. What it says it does is all that matters. If it is 75%, then you have 75% damage reduction.
Not too good for really late game where you would have 85% reduction. However, with this skill on, you can level a hero all the way to end game, and only have 7 armor. Meaning, it counters corrupt flesh and armor reduction builds.
Also, there is a constant 10% spell reflect chance. I have hit myself with my own atma beam before, because my opponent had this skill.
The magic damage reduction, is well.. magic damage reduction. All the stats offered by this skill are only active when the skill is active.
We have reason to believe it works with mana shield also. I have used it with mana shield, and it seemed to be what got me the win that game; my mana survived as long as my HP did, but if i left it on when my mana was gone... OWWWWW!
Any Questions?
***Edit, we posted at the same time***
I'm not sure exactly what you are saying didnot, but to clarify, the damage reduction on defend REPLACES your heroes damage reduction. Reduced damage (like the 200 reduced damage on Immortals Shield) Will still work with this skill though.