Conqueror rune interactions

So far Ive been using conqueror + on to great success you do more damage from your passive with it active because its basically just a 40% damage reduction with 100% more max hp in group fights

Although there is a certain amount of hp you need in order for your %hp damage to overcome your basedamage loss to be worth it I mean its always worth it since you are supposed to be tanking... but still

But I was wondering if conqueror is able to penetrate other forms of damage reduction such as when hits someone with multiple tentacles first is full damage rest do 50%

Has anyone else found anything cool with conqueror?

I think it would be pretty funny on zyra, say she gets a good knockup with r allowing her conqueror to charge up and then all of her plants are hitting a lot harder without doing as much reduced damage for a good 4 seconds.

Provided that conqueror`s true damge breaks thru these effects without being reduced.