Armor

Armor reduces the an amount of the incoming damage dealt on you. The more armor you have, the more the damage is reduced.

Guesses: I don't have a particular formula, but i think, 1 Armor = 1% dmg reduction. Meaning "Tough Times" Increases the armor by 14. Therefore it reduces the incoming damage by 14%. (likely highly incorrect)

I have a particular formula.

Damage reduction = Armor/(Armor+100)

This seems to work for repulsion armour at minimum, returning the correct 83.33% damage red.

This also means that you are never invulnerable, however, holding 1422 Tough times will cause a damage reduction high enough to round to 100%