I don't think so, I don't think it's hard capped but you can only get so much because of the current meta. I don't remember if it's capped or uncapped like NC/UN. Someone else should probably answer.
No you subtract your immune rate from the enemy's damage rate and use that to calculate the damage dealt. So as long as the enemy has above 100% damage rate (almost everyone does) they will still deal damage
erazor123 replied at 2016-6-14 07:08
yeh but if I have 100% immune rate I'm invincible right ?
I mean, I will take x*0 each attack..?
You can negate a ton, but you will most likely always take damage. But you can stack enough Immune and Defense/Kido Defense to take only 1-5 damage. So basically unkillable.