defensive duelist feat - pros & cons?

[bloodgroove]

Thinking of playing a human variant fighter with defensive duelist as my initial feet. I would also take the defense fighting style.
Would like to know possible pitfalls of starting this way. He would be rapier and shield type. My thoughts are it is better minimize
getting hit. Any thoughts would be appreciated.

[RSP]

I like DD on martials. Only real pitfalls are:

- your reaction is always used (or saved for possible use)
- you're usually best doing everything to up your AC to make the most out of the feat
- only for a single attack, so sometimes need to make a choice on which attack you're going to use it on

Not sure these are really "pitfalls" and it sounds like you're already okay with going with Defensive as your fighting style to get the added AC, so really just make sure you're okay keeping that reaction (so opt out of opportunity attacks and allow the Orc to go ahead and hit you if a Giant is on deck that same turn) for DD and you should be fine.

[Ganymede]

I like Defensive Duelist. It only works against melee attacks, though it does work against melee spell attacks.

I use it with a warlock of mine that pretends to be a swashbuckler.

[bloodgroove]

thanks for the thoughts...

[Caelic]

DD also couples very well with Drunken Master. Ensure that this attack misses you, then redirect it to someone else.

[Easy_Lee]

DD also couples very well with Drunken Master. Ensure that this attack misses you, then redirect it to someone else.

That's two reactions.

[Caelic]

That's two reactions.


Ugh. So it is.

[Dudewithknives]

Ugh. So it is.

It is not worth it, should have been a half feat that gave +1 dex.

[djreynolds]

I have used it and liked it. But I grabbed it at level 12.

Good for S&B who don't mind using a rapier and dual wielders.

Up to +6 AC

I would not personally grab it at 1st level and the same goes for resilient "something", your proficiency bonus isn't high enough yet.

I might grab shield master at first level.

[bid]

Thinking of playing a human variant fighter with defensive duelist as my initial foot.
FTFY
Only when you get a second one can you collectively call them "feet".:smallbiggrin:


But seriously, there are a few caveat:
- rogue 5 is strictly better, if you MC that way,
- BM's riposte also uses reaction,
- OA also uses reaction, you can't threaten skirmishers.

[RSP]

But seriously, there are a few caveat:
- rogue 5 is strictly better, if you MC that way,


Just curious, why would half damage on one attack be better than no damage?

[Grod_The_Giant]

Just curious, why would half damage on one attack be better than no damage?
They're slightly redundant, but since you can pick which one to use after the dice are rolled, it doesn't hurt to have both.

Probably the biggest weakness is that it only applies to one attack per round-- if you get multiple dudes coming after you, or even one dude with multiattack, you're going to have to gamble on when best to use it.

[Dudewithknives]

If you want to take defensive duelist wait until your proficiency bonus can make make a bigger difference.

At level 1 it only adds a +2 to ac.

Wait until like 8.

There are many better feats

Edit to expand:

If you use defensive duelist that costs your reaction so if you use it the first time the enmy hits you, you just gave them a free pass to walk away from you and hit someone else that dies not have as good of an ac as you should.

If you want to be sword and board defense guy take sentinel.

You should have a 14 dex if not a 16 if you are going finesse weapons. Wearing studded leather you should have 18 ac. That is very good at level 1. Defensive duelist is not needed.

You are kind of going in 2 different directions here. Dex based weapon but trying for high ac. Dex is made for light armor which will always have slightly lower ac than medium or heavy. You can still pull off good ac thanks to shield and defensive style, but you are going in different directions for it.

You have a much better ranged option than str based fighters and have many more options than a lot of builds but if you want to be captain AC and be a turtle, which works wonders, light armor is not the way to go.

[bid]

Just curious, why would half damage on one attack be better than no damage?
DD is not "no damage".
- At best, it's 6/20 of "no damage". Level 5 drops it to 3/20.
- Even if the DM rolls in front of you, the difference might not be enough to make a miss every round.
- And you can't avoid a crit.

The final nail in the coffin is that DD uses up a feat while UD comes for free with rogue 5.

[nirurin]

I was considering DD on my Swords Bard, but I also have the option of the Shield spell.

Both use a reaction.

DD would give +3 AC at level 5, +6AC at level 17+. Shield is always +5.

DD only works against a single attack. Shield works for the rest of the round.

Shield burns a spell slot. DD uses a feat.


I'm leaning towards Shield being the better option.

[Dudewithknives]

I was considering DD on my Swords Bard, but I also have the option of the Shield spell.

Both use a reaction.

DD would give +3 AC at level 5, +6AC at level 17+. Shield is always +5.

DD only works against a single attack. Shield works for the rest of the round.

Shield burns a spell slot. DD uses a feat.


I'm leaning towards Shield being the better option.

Defensive duelist also only works on melee attacks so is pointless vs an archer or ranged spell user.

[Talamare]

You are kind of going in 2 different directions here. Dex based weapon but trying for high ac. Dex is made for light armor which will always have slightly lower ac than medium or heavy. You can still pull off good ac thanks to shield and defensive style, but you are going in different directions for it.

Light Armor - 13 + Dex = 18
Medium Armor - 15 + Max 2 Dex = 17
Heavy Armor - 18 = 18

So, Light Armor has exactly equal AC as Heavy Armor

Medium Armor has less, but it's also the easiest one to achieve it's 'max' Armor Value

Only a few classes have Heavy Armor, and even if you have it. 15 STR is more than 14 DEX. Not to mention Dex has more usability than Str. Most nukes use Dex as a Defense, Initiative, and more skills use Dex.

But wait! Medium Armor Feat... no

[Dudewithknives]

Light Armor - 13 + Dex = 18
Medium Armor - 15 + Max 2 Dex = 17
Heavy Armor - 18 = 18

So, Light Armor has exactly equal AC as Heavy Armor

Medium Armor has less, but it's also the easiest one to achieve it's 'max' Armor Value

Only a few classes have Heavy Armor, and even if you have it. 15 STR is more than 14 DEX. Not to mention Dex has more usability than Str. Most nukes use Dex as a Defense, Initiative, and more skills use Dex.

But wait! Medium Armor Feat... no

Light armor does not have 3 ac, it has 2.
Also that is only 17 ac after he maxes out dex which is level 6 at least.

It is with max stats light 17
With only 14 dex medium is 17 ac, if for some reason he wants to take medium armor master it is 18 ac with 16 dex
Heavy has 18 base but needs 15 str or be a dwarf.

[Talamare]

Light armor does not have 3 ac, it has 2.

Whoops

Altho, you're arguably not meant to be able to afford 18 AC Heavy until roughly level 5~6 regardless

[RSP]

DD is not "no damage".
- At best, it's 6/20 of "no damage". Level 5 drops it to 3/20.
- Even if the DM rolls in front of you, the difference might not be enough to make a miss every round.
- And you can't avoid a crit.

The final nail in the coffin is that DD uses up a feat while UD comes for free with rogue 5.

With a high AC (which with taking Defensive is very possible), it's very effective at turning hits into misses.

It doesn't avoid a crit, but I think you misstated the cost, as 5 levels of Rogue is far from "free."

As the OP stated they're a fighter, a feat would be a heck of a lot easier to accept than 5 levels of Rogue would be. If you plan on getting extra attack before getting 5 Rogue that's at least character level 10 before you're using this ability.

And comparing a feat to a 5th level class ability shouldn't be even (no feat gives you spell slots and a few 3rd level spells known, or Extra Attack).

If you're already planning on going 5 Rogue it would be less useful due to both competing for Reaction, but having played with this feat, it is very effective.

[Dudewithknives]

Whoops

Altho, you're arguably not meant to be able to afford 18 AC Heavy until roughly level 5~6 regardless

It is still before you will get that 20 dex.

I have never seen a game go past level 3 or MAYBE 4 before someone who was made for plate had it.

Dex is a better stat than str for sure. Dex is the king stat in 5e.

It also highly depends on what archetype he is going.

I assume not arcane archer if his plan is shield and sword.

Battlemaster can fight however they want.

Samurai is not impressive to me, but still better than champion and either of them can go dex or str but neither needs DD before other feats.


Eldritch knight is great and honestly I see it going more dex based, but with shield as an option even less reason for DD. You could also take mage armor if you really wanted to, which is all dex.


In the end, as a variant human my level 1 feat would not be Defensive duelist no matter what my build was.

[Tanarii]

I have never seen a game go past level 3 or MAYBE 4 before someone who was made for plate had it.
You're playing with treasure rewards that dont match the DMG tables then. After your first, maybe even 2nd, Tier 2 hoard is when character can afford Full Plate by 'default'. So about level 6-ish.

Which is about 2 levels before you'd expect some really focusing on Dex to have Dex 20.

[Asmotherion]

I can think of only 1 way to judge it that is relative, and that is the Shield Spell. Why? Because they both boost your AC as a reaction.

Pros:
-Does not need a spell slot; A non caster, and even a non-commited caster (1/3 casters and even half casters) will be able to use it more freely than shield.
-Scales with level, and eventually becomes a better bonus than shield at +6

Cons:
-Lasts for a single attack, wile shield lasts untill the start of your next turn.
-Shield remains a net +5 AC bonus for a simple 1st level spell slot, great for any caster; Wile DD improves, +2/+3 AC for a single attack is far less impressive.
-By the time the bonus becomes greater than shield, Wizards can literally cast Shield at-will, and other casters have enough spell slots to virtually do the same.

My verdict: It's good on non-casters and not bad on 1/3 casters. Everyone else should probably get Magic Initiate instead of it, and even 1/3 casters could arguably get a lot more out of Shield than out of it.

[bid]

With a high AC (which with taking Defensive is very possible), it's very effective at turning hits into misses.

It doesn't avoid a crit, but I think you misstated the cost, as 5 levels of Rogue is far from "free."


- rogue 5 is strictly better, if you MC that way,

Yeah, but no.
You asked "why would half damage on one attack be better than no damage?"

So you are level 5-8 with a +3 proficiency. Assuming you can see the attack roll, DD will be useful 3/20 of the time. If you are attacked 4 times per round, it will be useful half the time. {17/20^4 ~ 0.52} Something like every 2 rounds you are missed 5 times, get hit 2 times, and DD saves you once. If the DM lets you see the result.

If your AC is high enough that the enemy needs to roll 17+, then yes, as soon as the DM tells you it's a hit and not a crit you can use it just as well as if you saw the DM roll. But with realistic AC19, half the hits aren't changed by DD. This means every 4 rounds, 10 miss, 4 hits, 1 DD hit, 1 DD save.

As you said, UD comes up late and requires MC. But clearly DD is a trap for rogues, and "half-damage" is much better than "no damage".


Returning to the current case: a shield and rapier guy.
- shield master is a better feat,
- sentinel is a better feat and use of reaction,
- battlemaster's riposte is a better use of reaction,
- dipping swashbuckler fits the dashing fighter RP concept better,
It's hard to find a case where DD can shine.

[RSP]

Yeah, but no.
You asked "why would half damage on one attack be better than no damage?"

So you are level 5-8 with a +3 proficiency. Assuming you can see the attack roll, DD will be useful 3/20 of the time. If you are attacked 4 times per round, it will be useful half the time. {17/20^4 ~ 0.52} Something like every 2 rounds you are missed 5 times, get hit 2 times, and DD saves you once. If the DM lets you see the result.

If your AC is high enough that the enemy needs to roll 17+, then yes, as soon as the DM tells you it's a hit and not a crit you can use it just as well as if you saw the DM roll. But with realistic AC19, half the hits aren't changed by DD. This means every 4 rounds, 10 miss, 4 hits, 1 DD hit, 1 DD save.

As you said, UD comes up late and requires MC. But clearly DD is a trap for rogues, and "half-damage" is much better than "no damage".


Returning to the current case: a shield and rapier guy.
- shield master is a better feat,
- sentinel is a better feat and use of reaction,
- battlemaster's riposte is a better use of reaction,
- dipping swashbuckler fits the dashing fighter RP concept better,
It's hard to find a case where DD can shine.

UD is a great ability, but it's not always better: any instance where DD makes a hit miss means that attack went from half damage to no damage. So how, in those situations, is UD "always better?" Factor in the cost of one feat vs 5 levels, and there's a very good argument to take DD.

And, yes, it's less effective on Rogues d/t UD. It's also less effective on Wizards with the Shield spell, or GWM Fighters who don't use finesse weapons. It's like saying Magic Initiate (Cleric) isn't as effective if you're a Cleric.

5e deals a lot with Action economy; I wouldn't suggest playing with builds that overburden either Bonus Actions or Reactions, unless you had a particular reason to do it.

And again, comparing a 5th level class feature to a feat isn't a good comparison for feats.

I found DD to come in handy quite a bit when I played it on a melee build. I took defensive as my fighting style, used a shield and was very difficult to hit, particularly when combined with Protection from Good and Evil. If 1 out 3 attacks a round would hit me, DD was usually enough to make that 1 hit miss. And you can do that all day long.

Again, in my experience I found it to be not only very effective, but very fun as well as it's always fun to turn hits into misses (when you're the target).

[bid]

UD is a great ability, but it's not always better: any instance where DD makes a hit miss means that attack went from half damage to no damage. So how, in those situations, is UD "always better?"
The same way "any instance where DDimproved critical makes a hit miss a crit".
If you move the goalpost to "in those situations" where you always roll 19, of course you will make it true.


I clearly delineated why "no damage" was a statistical lie... with facts. There's no point in discussing statistically insignificant cases.

[RSP]

The same way "any instance where DDimproved critical makes a hit miss a crit".
If you move the goalpost to "in those situations" where you always roll 19, of course you will make it true.


I clearly delineated why "no damage" was a statistical lie... with facts. There's no point in discussing statistically insignificant cases.

I don't think goalposts were moved: you stated one is always better than the other. Either, you meant 5 levels of Rogue is always better than taking DD (which is not a true statement for a number of reasons, the simplest of which is most builds can't afford it), or you meant using UD is always better than using DD (also not a true statement as it's better to take 0 damage than it is to take half damage).

It's also not a lie: if you turn a hit into a miss, you take "no damage." Its also not statistically insignificant: even at 1st level, a 10% reduction in hits is significant, as is the 30% reduction your getting at high level play.

[Tanarii]

or you meant using UD is always better than using DD (also not a true statement as it's better to take 0 damage than it is to take half damage).
If you can't understand how taking 10%-30% less damage is always less than taking 50% less damage, then there's something wrong with your math skills.

[Ganymede]

If you can't understand how taking 10%-30% less damage is always less than taking 50% less damage, then there's something wrong with your math skills.

Your math is actually a bit messed up here.

Based on what I saw above, you're calculating DD's average damage prevention by translating the bonus to AC into a percentage decrease in damage.

The error your making here is that you're averaging in all of the attacks that are misses before DD is used, but are not doing the same for UD. This results in a comparison that is not apples-to-apples. A more apt comparison results in 20-60% compared to 50%.

If it helps illustrate things, imagine a scenario where someone gets hit 50% of the time. Applying UD is easy, the damage you receive is reduced by 50%, and it doesn't really depend on the miss chance. On the other hand, look at DD at +6 AC. That reduces the hit chance to only 20%, meaning the damage ends up only being 40% of what it would have been, on average.

[Tanarii]

Your math is actually a bit messed up here.
Curse you! (In the kindest possible way, of course.) Hoisted on my own petard.

You are absolutely correct. It's 50%*HitChance*Damage vs (Prof*5)%*Damage. (Unless I just made another error.)

So DD is better when (Prof/10) > Hit Chance. Assume 60% hit rate (forum standard), then they break even at +6 proficiency bonus. Although 60% is high for monsters, 40-50 is generally more accurate. So they probably start to break even at a 4-5 prof bonus.

[mephnick]

I always think about it, but find it too limited to waste a feat on for the reasons that have already been stated.

It feels like a giant opportunity cost, not just the feat, but every turn when I'd decide to use it or not. Like, if I used it and blocked 1 out of 3 attacks and then I missed out on an important OA I'd be hating my decision to take the feat right about then.

[GlenSmash!]

I find it good on a Grappler that does not have UC.

If the target is grappled and prone, it will be attacking you with disadvantage. DD works great for those few hits that get through (hopefully only one a round)

Otherwise, I would pass on it.

[Specter]

Pros: It's a permanent Shield.
Cons: It's a bit worse than Shield at low levels, and only stops one attack.

That's as simple as it gets.

All the unyielding mathematicians above are forgetting that there are instances where not getting hit can be, in fact, 10 times better than taking half damage, even if Uncanny Dodge is after the fact.

- Concentration: If you're concentrating, you definitely don't want any attacks breaching in.
- Near death: when you have less than 1/4 of your HP, reducing damage in half might not matter at all, whereas defending the blow might save you.
- Avoiding effects: some attacks will carry nasty effects with them, like poison, paralysis or disadvantage, and cutting damage in half won't save you from those.

[Easy_Lee]

The question is not whether it's beneficial. The question is: are there better, competing feats?

It's hard to compare DD to something like GWM. But it does not compare favorably to shield master.

[nirurin]

Pros: It's a permanent Shield.
Cons: It's a bit worse than Shield at low levels, and only stops one attack.

That's as simple as it gets.

All the unyielding mathematicians above are forgetting that there are instances where not getting hit can be, in fact, 10 times better than taking half damage, even if Uncanny Dodge is after the fact.

- Concentration: If you're concentrating, you definitely don't want any attacks breaching in.
- Near death: when you have less than 1/4 of your HP, reducing damage in half might not matter at all, whereas defending the blow might save you.
- Avoiding effects: some attacks will carry nasty effects with them, like poison, paralysis or disadvantage, and cutting damage in half won't save you from those.



DD also doesn't use spell slots, which is a plus. But then, it uses a feat, which is a big minus.

The Shield spell uses up a level 1 slot each time, which is a limited resource, which is a minus. But it recharges slots every long rest (or short rest for warlock slots), which is easier to get than an extra feat. Feats are a much more limited resource. And you can get the shield spell from other sources too sometimes, like scrolls I guess.

[Specter]

The question is not whether it's beneficial. The question is: are there better, competing feats?

It's hard to compare DD to something like GWM. But it does not compare favorably to shield master.

It depends on who we're talking about.

Barbarian: If you do take some levels of Rogue, you should already be using a rapier, so it can't be bad. Shield users can also get a kick out of it.
Bards: Valor Bards, sure. Lore Bards probably don't want to be around melee, and in an emergency there's Cutting Words.
Clerics: so few cleric subclasses get reaction uses that a permanent one is very welcome addition.
Druid: not worth it because you'll usually be wild shaped in melee.
Fighter: Fighters other than Eldritch Knights get few reactions, period. Even a Battlemaster with Riposte will eventually run out of dice and/or want to preserve his skin on a hit. Plus, lots of ASIs.
Monk: It's hard to make a statement pro or against, because it's very good, but Monks need to boost at least two stats.
Paladin: Same as Monk.
Ranger: Same as Monk.
Rogue: You'll eventually get Uncanny Dodge, which lessens the need for this, but as stated above sometimes you don't want to get hit at all.
Sorcerer: Shield is there for you, so there are probably better choices out there.
Warlock: No Shield and no good reactions? Then yeah.
Wizard: Same as Sorcerer.

[nirurin]

It depends on who we're talking about.

Barbarian: If you do take some levels of Rogue, you should already be using a rapier, so it can't be bad. Shield users can also get a kick out of it.
Bards: Valor Bards, sure. Lore Bards probably don't want to be around melee, and in an emergency there's Cutting Words.
Clerics: so few cleric subclasses get reaction uses that a permanent one is very welcome addition.
Druid: not worth it because you'll usually be wild shaped in melee.
Fighter: Fighters other than Eldritch Knights get few reactions, period. Even a Battlemaster with Riposte will eventually run out of dice and/or want to preserve his skin on a hit. Plus, lots of ASIs.
Monk: It's hard to make a statement pro or against, because it's very good, but Monks need to boost at least two stats.
Paladin: Same as Monk.
Ranger: Same as Monk.
Rogue: You'll eventually get Uncanny Dodge, which lessens the need for this, but as stated above sometimes you don't want to get hit at all.
Sorcerer: Shield is there for you, so there are probably better choices out there.
Warlock: No Shield and no good reactions? Then yeah.
Wizard: Same as Sorcerer.

Warlocks do get a shield, as well as Shield.

[Dudewithknives]

Warlocks do get a shield, as well as Shield.

Only Hexblades, but just about all of them are Hexblades now so there you go.

Also, this ignores the idea that everyone can use a reaction for AoO.
This is like giving every enemy the effects of the Mobility feat or the Swashbuckler ability for a 10 - 20% chance they might miss you on one attack. Most campaigns are not making it to the land of +5 and +6 proficiency.

If it was a half feat that gave +1 Dex as well, sure.

[Tanarii]

It depends on who we're talking about.Right. DD is pretty clearly a Dex Fighter, Ranger, and maybe some Bards/Warlocks Feat.

Which is fine. Not every Feat has to be for everyone. Nor does every feat have to be outright broken, like the big 3 (GWM, PAM, SS).

[RSP]

Warlocks do get a shield, as well as Shield.

It's tough to really say a Warlock casting Shield is worth it, particularly after level 2: you're constantly losing out due to limited slots at max level.

[RSP]

The question is not whether it's beneficial. The question is: are there better, competing feats?

It's hard to compare DD to something like GWM. But it does not compare favorably to shield master.

I like it better than Shield Master on some builds.

We're playing SKT right now and SM is pretty much useless on our front liner, however, if you cause a hit to miss against a Fire Giant, you just saved ~28 damage, and you can use DD every round. That's a huge effect in terms of staying up, not to mention the added fun of thwarting the attack.

[bid]

We're playing SKT right now and SM is pretty much useless on our front liner, however, if you cause a hit to miss against a Fire Giant, you just saved ~28 damage, and you can use DD every round.
Still, using DD every round means "no damage" about a third of the time. 100% save 33% of the time is 33% damage saved overall.

SKT ends at level 11, where proficiency is +4. Fire giants have +11 hit, and will hit on 9+ against AC20. Lets assume the first hit of the next 12 rounds will be (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20), shuffled. On 4 of those rounds (9, 10, 11, 12) DD will save from damage, and 8 of those rounds (13, 14, 15, 16, 17, 18, 19, 20) DD will be wasted. DD will save you from damage once every 3 rounds.

So yeah, it's cool but it's far from perfect.

[Tanarii]

Still, using DD every round means "no damage" about a third of the time. 100% save 33% of the time is 33% damage saved overall.

SKT ends at level 11, where proficiency is +4. Fire giants have +11 hit, and will hit on 9+ against AC20. Lets assume the first hit of the next 12 rounds will be (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20), shuffled. On 4 of those rounds (9, 10, 11, 12) DD will save from damage, and 8 of those rounds (13, 14, 15, 16, 17, 18, 19, 20) DD will be wasted. DD will save you from damage once every 3 rounds.

So yeah, it's cool but it's far from perfect.Are we comparing a straight rogue to a rogue here? Because AC 20 seems unlikely if so. Or is it a Fighter/Rogue Dex-tank we're talking about?

Also we need some more rigorous math here.

------------
Damage you take from two attacks is:
2 attacks = 2*H*Dam

--------
Damage you take from 2 attacks with DD is:
first attack: {(H-DD)*Dam}
Second attack: (1-DD)*{(H-DD)*Dam} + DD*{H*Dam}

Total: 2*H*Dam - 2*DD*Dam + DD^2*Dam
2 attacks with DD = (2H-2DD+DD^2)*Dam

------
Damage you take from 2 attacks with UD is:
First attack: {H*Dam*UD}
Second attack: (1-H)*{H*Dam*UD} + H*(H*Dam)

Total: 2H*Dam*UD -H^2*Dam*UD-H^2*Dam
Since UD = 1/2 we can reduce this to:
2 attacks with UD = {(2+H)/2}*H*Dam
------------



If we assume chance of getting H by a fire giant is 60%, chance of DD +4 is 20%, and Dam = 28:

Normal = 33.6
DD = 23.52 (70% of normal)
UD = 21.84 (65% of normal)

If H changes this changes, if DD were only +3, it'd change.

Edit:
For those interested, the final percent of normal damage will be:

DD:
(2H-2DD+DD^2) / (2*H)

UD:
(2+H)/4

[RSP]

Are we comparing a straight rogue to a rogue here? Because AC 20 seems unlikely if so. Or is it a Fighter/Rogue Dex-tank we're talking about?

Also we need some more rigorous math here.

------------
Damage you take from two attacks is:
2 attacks = 2*H*Dam

--------
Damage you take from 2 attacks with DD is:
first attack: {(H-DD)*Dam}
Second attack: (1-DD)*{(H-DD)*Dam} + DD*{H*Dam}

Total: 2*H*Dam - 2*DD*Dam + DD^2*Dam
2 attacks with DD = (2H-2DD+DD^2)*Dam

------
Damage you take from 2 attacks with UD is:
First attack: {H*Dam*UD}
Second attack: (1-H)*{H*Dam*UD} + H*(H*Dam)

Total: 2H*Dam*UD -H^2*Dam*UD-H^2*Dam
Since UD = 1/2 we can reduce this to:
2 attacks with UD = {(2+H)/2}*H*Dam
------------



If we assume chance of getting H by a fire giant is 60%, chance of DD +4 is 20%, and Dam = 28:

Normal = 33.6
DD = 23.52 (70% of normal)
UD = 21.84 (65% of normal)

If H changes this changes, if DD were only +3, it'd change.

Edit:
For those interested, the final percent of normal damage will be:

DD:
(2H-2DD+DD^2) / (2*H)

UD:
(2+H)/4

Math isn't my specialty, but somehow factor in "F", the fun of deflecting a Giant's great sword with a rapier, and it looks good. Thanks for working that out.

[bid]

Are we comparing a straight rogue to a rogue here? Because AC 20 seems unlikely if so. Or is it a Fighter/Rogue Dex-tank we're talking about?
This is DD's raw value. Not a single word about rogue was said.

Damage you take from 2 attacks with DD is:
first attack: {(H-DD)*Dam}
Second attack: (1-DD)*{(H-DD)*Dam} + DD*{H*Dam}
It's (1-H) here. You use DD when hit, you do not know what the DM rolled.

(1-H)*{(H-DD)*Dam} + H*{H*Dam}

[Tanarii]

This is DD's raw value. Not a single word about rogue was said.

It's (1-H) here. You use DD when hit, you do not know what the DM rolled.

(1-H)*{(H-DD)*Dam} + H*{H*Dam}
No, it's not. I made that mistake at first too. You use DD on the second attack only when DD was not used on the first, whether it wants used because of hit or a miss. That's 1-DD, multiplied by the same damage for using DD. If you did use DD on the first attack, you take the full H*Dam.

Thus, (1-DD) chance of DD damage on second, plus DD chance of full damage on the second.

To look at it another way, you split 100% of second attack damage up into (did not use DD) + (did use DD).

[bid]

No, it's not. I made that mistake at first too. You use DD on the second attack only when DD was not used on the first, whether it wants used because of hit or a miss. That's 1-DD, multiplied by the same damage for using DD. If you did use DD on the first attack, you take the full H*Dam.

Thus, (1-DD) chance of DD damage on second, plus DD chance of full damage on the second.

To look at it another way, you split 100% of second attack damage up into (did not use DD) + (did use DD).
You are conflating "I used DD" with "DD worked".

You use DD whenever you get hit, which is 60% of the time in your example. The fact that it was helpful 20% of the time is only incidental.


EDIT: wasn't clear enough, simplified to the heart of the matter.

[Easy_Lee]

I like it better than Shield Master on some builds.

We're playing SKT right now and SM is pretty much useless on our front liner, however, if you cause a hit to miss against a Fire Giant, you just saved ~28 damage, and you can use DD every round. That's a huge effect in terms of staying up, not to mention the added fun of thwarting the attack.

Well, in that instance the trouble with giants is they have about a +11 to hit. Assuming 21AC (plate, shield, ring of protection or similar) and +3 from defensive duelist, they still hit you on a roll of 13. We can do the math.

Expected damage before DD = 10/20 * 28 = 14
Expected damage after DD = 7/20 * 28 = 9.8

And you can only use it on one attack, which may or may not come up in a given round.

[bid]

they still hit you on a roll of 13. We can do the math.

Expected damage after DD = 7/20 * 28 = 9.8
Oh that dreaded off-by-one, why does it keep killing us when we least expect it!:smallbiggrin:

[Easy_Lee]

Oh that dreaded off-by-one, why does it keep killing us when we least expect it!:smallbiggrin:

Heh, oops. Well, 8/20 instead of 11/20 then. But the point stands. You're saving yourself from perhaps 4 damage per round.

[Tanarii]

You are conflating "I used DD" with "DD worked".

You use DD whenever you get hit, which is 60% of the time in your example. The fact that it was helpful 20% of the time is only incidental.


EDIT: wasn't clear enough, simplified to the heart of the matter.
No, I'm not. You only CAN use DD on the second attack if you did not on the first. You use it DD of the time on the first attack. Therefore you cannot use it DD of the time on the second attack, and can use it 1-DD of the time on the second attack.

Edit: there is no separate DD worked or DD used. You use it if it will work. You don't if it will not.

[bid]

Edit: there is no separate DD worked or DD used. You use it if it will work. You don't if it will not.
That's not how most tables will play it.
Do you really believe "potentially causing the attack to miss you" actually means it's up to you to calculate it right?

You have a giant that needs 9+ to hit.
How do you know the DM rolled 9-12 and not 13+?
Do you really believe the DM must tell you he rolled 15?

[djreynolds]

I have used defensive duelist. It is a solid feat, IMO. But after level 5.

You can use this every round, and though it eats up your reaction, rarely do DMs allow their beasts to get smacked around with AoO.

I rarely see attacks of opportunity at our table as a player just because of the DM.

I recommend the feat for any S&B fighter with a dex of 13 or better and TWF fighters.

But grab shield master as 1st level, because every round you can use that bonus action.

And even if you grab sentinel... now you have a choice of which to use. Perhaps getting in an attack is worth it if you have the hit points, and on the other end getting in attack may not be worth it because the next hit could kill you.

I would grab this feat at 8th or 12 level. But grabbing it at 1st level... could save your life as you only have 13-14 HP.

[RSP]

That's not how most tables will play it.
Do you really believe "potentially causing the attack to miss you" actually means it's up to you to calculate it right?

You have a giant that needs 9+ to hit.
How do you know the DM rolled 9-12 and not 13+?
Do you really believe the DM must tell you he rolled 15?

Not sure how "most tables" play it, but we usually announce our rolls (that is, the total of the die roll+mod), as players, to see if we hit an opponents, such as "Does an 18 hit?"

Not sure why it isn't fair to have the DM do the same, otherwise your giving enemies with these kinds of abilities an advantage over the Players.

[bid]

Not sure how "most tables" play it, but we usually announce our rolls (that is, the total of the die roll+mod), as players, to see if we hit an opponents, such as "Does an 18 hit?"

Not sure why it isn't fair to have the DM do the same, otherwise your giving enemies with these kinds of abilities an advantage over the Players.
Against adversarial DM, sure.

Not a good analogy. The AC is constant and guessable, while the attack roll is not.


But I can understand why you'd feel DD is ok, since knowing the enemy attack roll triples its value.

[RSP]

Against adversarial DM, sure.

Not a good analogy. The AC is constant and guessable, while the attack roll is not.


But I can understand why you'd feel DD is ok, since knowing the enemy attack roll triples its value.

Has nothing to do with an adversarial DM. That's just how we play. What's good for the Players is good for the DM; any advantage the PCs get from that procedure, the NPCs get as well.

Similarly, we don't call out spell names when casting, just that we're casting. I don't expect my DM to lie about what was being cast if it's Countered, anymore than I would lie if my PC's spell was Countered.

[djreynolds]

I always think about it, but find it too limited to waste a feat on for the reasons that have already been stated.

It feels like a giant opportunity cost, not just the feat, but every turn when I'd decide to use it or not. Like, if I used it and blocked 1 out of 3 attacks and then I missed out on an important OA I'd be hating my decision to take the feat right about then.

But having an option is nice.

As a wizard I prepare many reaction spells... shield, feather fall

And sometimes I have competing bonus actions... but it gives me a choice

Our DM rarely gives us AoO

DD is a good feat on a S&B fighter, but a specific build. Usually a fighter who dipped rogue for expertise in athletics and is using a rapier.

DD's issue is not having a 13 in dexterity, but needing a finesse weapon. You may not find a magical rapier or short sword, and you may need that magic war hammer and now defensive duelist is useless

And if the OP is a dex based fighter... he may want to go TWF. As shield master may be useless if he dumped strength.

We need the OPs stats

And if you do dip rogue, obviously going past 5th is silly because uncanny dodge is there.

And a ranger just doesn't have the ASI/feats

It worked for my build because I was a champion with a dip of rogue for expertise

[Tanarii]

That's not how most tables will play it.
Do you really believe "potentially causing the attack to miss you" actually means it's up to you to calculate it right?

You have a giant that needs 9+ to hit.
How do you know the DM rolled 9-12 and not 13+?
Do you really believe the DM must tell you he rolled 15?
Okay. I see your point. If we want to assume you'll use it automatically on the first hit, because you don't know if it will change it to a miss but you're gonna use it and find out, that will change its usefulness dramatically, and affect the formula. I'll rework them for that assumed usage of the Feat and edit this post with the replacement formula.

Edit:

Damage you take from 2 attacks with DD is:
first attack: {(H-DD)*Dam}
Second attack: (1-H)*{(H-DD)*Dam} + (H)*{H*Dam}

Total: (2*H-2*DD+H*DD)*Dam

Fraction of normal damage is:
(2*H-2*DD+H*DD)/2*H


For H=.6, DD=.2, Dam = 28
DD = 25.76 DPR (77% normal)


But I can understand why you'd feel DD is ok, since knowing the enemy attack roll triples its value.It adds about 7% DPR taken in this case.

[bid]

Normal = 33.6
DD = 23.52 (70% of normal)
UD = 21.84 (65% of normal)(only using DD when it causes a miss)



For H=.6, DD=.2, Dam = 28
DD = 25.76 DPR (77% normal)(always using on the first hit)

Thanks for the numbers. That was useful.
77/70 ~ 10% variation between both rulings. Not as big as I thought.


It looks like uncanny dodge might make a fair feat, if a bit stronger than defensive duelist.