100% Damage taken reduction? that can't be right

Ok so i'm currently looking around all possible ways to reduce incoming damage from attacks, and found an interesting combination.

base tamage you take is 100%

-33% - Strength of Blood (keystone from timeless jewel Lethal Pride, Kaom)
for -33% damage reduction from Strength of Blood, we'd need to take all nodes that increase maximum life recovery per second from leech (except the ones in the far top-right) + Vaal Pact.

This skill reduces all damage taken by 1% for every 2% of maximum recovery per second from leech. The base value for this is 20%, with Vaal Pact is goes to 40%. Add all the nodes from the tree (equals +65%) and we should get 40x1.65 = 66% maximum recovery, So it means 33% damage reduction.

Now we see other sources of reducing damage taken:
-23% - Fortification (from points in the skill tree)
-20% - Enfeeble (Curse. Value from effect at unique enemies from a level 23 gem)
-25% - Indomitable Resolve (marauder-only, hidden ascendancy point)

and that gives us... 101% damage reduction? Does that mean we literally get immune to all sources of damage? I doubt it.

And if we cast Enfeeble as an aura, that would lessen the effect by 25%, leaving us with 15% reduction only. Still, that makes the total thing 96% which is basically all of it. Combine it with high phys damage and you'll recover all health lost instantly after taking a hit while also not needing to constantly cast the curse. For now i'm interested in seeing what Cyclone + Bloodseeker Claws does with all this.

I'm looking foward to test this one out myself but i'm currently lacking the resources to redo my build, so i want to share this with you people earlier.

Multiplicative, not additive. So no.

are you sure? PoB doesn't treat it as multiplicative. I tested now in a clear build, allocating both Indomitable Resolve and Strength of Blood has the same -25% and -33% to hitpool if you remove them, so it looks to be additive.

All of the modifiers you mentioned are "less damage", not "reduced damage". Less/More stack multiplicitively with other sources.

Enfeeble is also "deal less damage". Even if it was "deal reduced damage", you wouldn't stack additively with damage reduction because the monster dealing the damage and you taking the damage are different steps in the calculation.