Title. For each Rank of Lightbringer, you deal 5% more damage to and have +1 damage reduction against Abaddon and his demonic servants.
Now, see the bolded part... well i dont get it

Since it says +1, i feel it means that i already have some sort of damage reduction, does this refer to armor, effectively boosting it?
Or, does it mean, if some tormented creature hit me for like 50 dmg, i would actually recieve 47 dmg if i have the third tier in the title (assuming i have 0 AL)... ?
Or something third...