Post/Author/DateTime	Post
#1 JoshuaGoudreau May 14, 2015 19:41:58	I ran across something interesting today while converting some old material to 5e and I couldn't really find an answer in the DMG or MM.  I may have missed it and if I have I apologise, 5e is still new to me.   I'm not sure how to handle creatures with natural armor who also wear armor.  My assumption is that I would use whichever base AC is higher than add Dex for the final result.  However, the previous edition logic stands of stacking bonuses, however this will lead to an absurdly high AC for the bounded accuracy of the current edition.   My example is this:   If we take a troll with an AC of 15.  4 of that is derived from natural armor and 1 from Dex.  Now, what happens if we put that troll in a breastplate with a base AC of 15?  Does it get an AC of 16 (base 10, +5 armor, +1 Dex) or 19 (base 10, +5 armor, +4 natural armor, +1 Dex)?  Now the bounded accuracy of the current rules implies that the higher armor rating would be the base to work from for an AC of 16, however logic would say its natural armor provides additional protection for an AC of 19.  So which is it?   Now, to make matters more complicated, what happens if we give the troll a level of barbarian and it gains Unarmored Defense (add Con bonus to AC)?  This removes additional armor from the equasion but it still gives him an AC of 20 and that seems very high (base 10, +4 natural armor, +1 Dex, +5 Con).  Give him the allowed shield and he goes up to 22, an extremely high AC in fifth edition.   So which of these is the correct method for calculating AC?  I want to give my players a challenge but not necescarily kill them with a monster they can't hurt.   Thoughts?
#2 AaronOfBarbaria May 14, 2015 22:12:43	In my opinion, natural armor is not a bonus to AC, it is an AC calculation - that clarifies when it does, or doesn't, apply.   For your troll example, the troll can choose from the following calculations for their AC: Natural Armor for an AC of 14 + dexterity modifier. Wearing armor for an AC of whatever base the armor sets + whatever dexterity modifier is or isn't allowed (a breastplate +1 giving an AC of 15 + dexterity modifier (or 2, whichever is lower) to follow your example). Barbarian Unarmored Defense for an AC of 10 + dexterity modifier + constitution modifier. I handle things this way because it is how 5th edition appears to handle things (since the only "natural armor" type of benefit we see the nuts & bolts of is the draconic sorcerer's Draconic Resilience feature that makes their AC when not wearing armor 13 + dexterity modifier, which is distinctly different from giving a +3 bonus to AC).
#3 Tempest_Stormwind May 14, 2015 22:28:08	Armor Class in 5e is not a single number with modifiers, like almost everything else. Instead, each source of armor you have provides a separate AC equation, and you pick one. If you have AC modifiers, like from a ring of protection, you apply that to whichever equation you use.   In short, I see things exactly the same way Aaron does. I'd also like to point to Barkskin, which uses an unusual mechanic... largely because of this method of computing ACs, it seems.
#4 JoshuaGoudreau May 21, 2015 20:42:56	Okay thanks guys.  It seems consistent with the game design to supplant the troll's natural AC base with that of the breastplate in the above example.  I want to create an interesting character for the party to fight but not one that will be too difficult to hurt.     The issue came about while converting the old Necromancer book Bard's Gate to 5e.  The gnoll stronghold has a troll with a level in barbarian who has hammered a large sheild into a breastplate and wears it into battle.  While interesting and unique in 3e it posed some issues in 5e.  I will likely give him the breastplate and change his level in barbarian to a level in fighter since he would lose his Unarmored Defense ability.
#5 JoshuaGoudreau May 21, 2015 20:57:46	Actually, for simplicity's sake I'll probably drop the class level and go with the troll wearing a breastplate.  The class level doesn't really add anything thematically to the character and it will make conversion simpler.  The characters will never know if the troll has a class level so I don't feel it serves a purpose.