Re: Magic Resistance
I took the liberty to split your post, as it is better dealt in its own thread.
1) Well, first off, there isn't really an ability that directly reduces magic resistance. You are probably talking about Natural Order and Veil here. While the description of both depict a different way of achieving increased damage, both work the same. For both an ability is added to the affected units that basically grants them negative magic resistance, thus increasing damage.
2) If they can be affected, the amplification will work. As previously stated, there's no direct magic resistance reduction.
3) The above.
4) Every magic resistance changing ability stacks with each other.
5) Not at all.
Sidenote: Natural Order and Veil of Discord use abilities to achieve their goal, the other amplification abilities: Holy Penitence, Orchid's, Plague or Soul Catcher use a triggered system which utilizes the already reduced damage for their amplification.