Bloodstained Blade Comboing?

I feel like shadow touch is a must run on warlock unless you're going only spell. If you haven't tried out the Kris dagger with shadow touch and bloodstained it's a great combo. It's only 1hp a swing if you're hitting your blows, and the additional 7 magic damage you get on the kris dagger makes a lot bigger difference due to attack speed. Something I'm very curious about and would like to test though (since it could further heighten this combo) is if another warlock hits you with blow of corruption while in demon form. Since the demon form tick damage is defined as negative percent max health healing, and blow of corruption's 80% reduction does effect max health healing in some capacity, would it reduce the drain?

I could see a Warlock duo going no spell, full plate, blow of corruption and demon form. If you hit in hand with blow of corruption, it should only do about ~10-12 damage with plate armor (maybe even less if you use a really bad dagger on super high armor rating), and if the 80% reduction does take effect, it would be (150 average max hp -> 1.75 hp a second over 12 seconds is about 21 damage) but with reduction would only amount to about 4 damage over 12 seconds. To top this all off, if one of the warlocks forego blow of corruption to go lifesteal spell, I think you could easily out-tank a barbarian because life-steal wouldn't be affected by blow of corruptions 80%. I wouldn't necessarily know the stats, but with demon form does warlock have the highest potential armor rating? Finding a way to minimize the health cost could be very strong.