Armorer Damage Optimization

 I think I've come around to the opinion that the Battle Smith is probably a more powerful subclass than the Armorer, but I still have a deep love and affection for the Armorer, and I suspect that if I ever get a chance to play one in an ongoing campaign (boy, I wish I had more friends eager to DM - if I could be playing four nights a week I'd consider that really great) I might stick to the Armorer as my subclass of choice.

Now, I was first drawn to the Armorer for their tanking capabilities, and the Guardian model certainly gives you a bit of that semi-taunt ability on your weapon attacks.

But D&D is a game that doesn't necessarily need tanks and healers the way a game like WoW does, and I think there's a strong argument to be made that maximizing damage is the better strategy - indeed, it can even help with a game's pacing by ending combat encounters faster (I love combat, but it's by far the slowest aspect of the game).

So, I wanted to figure out what the best options for maximizing damage on an Armorer would be. Naturally, there are some arguments to be made that multiclassing would be the best choice - perhaps getting enough Wizard levels to get insane spells like Conjure Minor Elementals. But at a certain point, we start to lose that Artificer identity, so I'm planning on doing what I generally prefer with any character and do a single-class build.

Let's talk about some of the challenges we run into:

First off, the Armorer is limited to basically one kind of weapon at a time. All count as Simple weapons, so that the armorer doesn't need to get new weapon proficiencies (like the Battle Smith or Artillerist) and lack some of the other limiting properties that might cause problems for a character relying on Intelligence for their attacks.

What this means, though, is that a lot of the weapon-focused feats that can really boost damage are left out of reach for us: None of our weapons are Heavy, so we can't use Great Weapon Master. None are covered in Polearm Master's categories (which are Quarterstaffs, Spears, and then Heavy Reach weapons - the Force Demolisher has Reach, but not Heavy). None are Light, either, so no Dual-Wielder.

The Dueling fighting style could work for us, as each of our weapons are one-handed and we won't have a weapon in the off-hand, but taking a Fighitng Style feat doesn't boost any ability scores.

Thus, I think we really need to lean into the fact that we're an Int-based spellcaster for our damage boosts.

Again, sadly, some of the spells that work great with characters that make attacks aren't available to us - Spirt Shroud and Conjure Minor Elementals. We can get the latter if we are playing specifically in Eberron - taking the House Lyrandar Heir background, and thus getting Mark of the Storm, and then taking Potent Dragonmark at level 4 would allow us to get CME at level 7. The downside is that this background doesn't boost Intelligence. (I actually think this is amazing on a Monk, who can even Flurry of Blows on the same turn they cast the spell - though there's a little ambiguity over whether a non-caster gets the Mark of the Storm spell list.)

Starting at level 5, having a Homunculus Servant and casting Dragon's Breath on it at the start of combat (a bonus action) is probably going to be standard practice for most 5.5 Artificers. At 11, we'll pack Lightning Bolt into our Spell-Storing Item and hand it to the Homunculus, who should be able to cast it every turn in combat unless we have a very long day of fights.

But the Homunculus stuff is, honestly, probably just going to be the standard for every Artificer (sorry Alchemists and Cartographers, who don't get a good 3rd level damage spell).

What of ourselves?

    Armor Models:

Well, of our three armor modes, we have a ranged and two melee options. Obviously, going Infiltrator is going to be the safest route. I'll say if we want to prioritize damage-dealing, we might skip the Guardian. So, the question becomes who deals more damage: Infiltrator or Juggernaut?

The Juggernaut's Force Demolisher does have a higher damage die, but the Infiltrator's Lightning Launcher also has some riders that might change that math.

The Force Demolisher does 1d10 Force damage, so if we're looking at a +4 to Int (which we'll probably have by level 4) we're talking about 9.5 damage on average per hit. At level 15, this changes to 2d6, and we probably have +5 to Int, so we're talking probably 12 damage on a hit.

The Lightning Launcher does 1d6 damage, but that's not strictly true: once per turn, we can add 1d6. Thus, at levels 3 and 4, it effectively does 2d6, or 11 on average with a +4 to Int. Then, at level 15, the damage increases to 2d6, but we still get that extra 1d6. Clearly, at levels 3-4, and then levels 15+, the damage is strictly better than the Force Demolisher. But at levels 5-14 (where we're most likely to spend the most time playing unless it's a high-level campaign) who wins? Well, 1d10 twice is basically 11 on average. 1d6 twice is 7, but then we have an additional 3.5, which is 10.5 - however, we're more likely to get that bonus d6 than either specific attack, because even if we miss on the first attack, we might be able to add it to the second. Thus, if we have, say, a 60% chance to hit, we've then got an 84% chance to get that extra d6 (because the 40% chance to miss becomes a 16% chance to miss on both shots).

So, 11x60% is 6.6, and then 7x60% is 4.2, plus 3.5x84% is 2.94, so the Lightning Launcher is actually doing 7.14.

Ah, but I forgot Crits!

Well, it's basically 5.5/20 times 2 (which is .55) versus 3.5/20 times 2 (which is .35) (oh duh, dividing by 20 and then multiplying by 2 is just dividing by 10) and then some really complicated math regarding whether the bonus d6 crits (because we can't know ahead of time if we're going to crit on our second attack after we make our first... do we just add the .175? Let's say that and if someone sees a flaw in the math, they can sue me). Ok, so we're just saying that .525. That means that the crit bonus is still better for the Force Demolisher, but only by .025, which does not make up for it.

    Spells:

So, the Lightning Launcher seems to be the highest-damage option here, at least in raw output, at all levels. But how can we enhance it further? (And might the Force Demolisher wind up having some extra edges because of its forced movement?)

Again, by level 5, my guess is that we'll mostly be casting Dragon's Breath on our Homunculus Servant to get a quick burst of 3d6 damage in a cone each turn. So, if we have spells we want to use to increase our damage, they've got to beat that (and remember that AoE spells are going to get tons more value if we have a target-rich environment).

Web is a solid spell that can play nicely with the Juggernaut's ability to knock enemies around the battlefield - if they get out, you can knock them back in. But it's hard to quantify precisely how much damage that translates to.

Heat Metal is a solid choice, especially if you use it on an item that the foe cannot quickly discard, like metallic armor. 2d8 damage is 9 on average, which is a little less than 3d6 (10.5 average) but there's no save against it. One of the really great benefits, though, of Dragon's Breath is that it's a bonus action to cast, and if we're doing it on our Homunculus, we don't need to worry about any action economy loss after that.

Once we get 3rd level spells at level 9, we get a few more options. Naturally, we can use our own spell slots to cast Lightning Bolt, which is pretty solid even against a single target, but best if we can get a bunch of enemies together in a line. (If the targets have a 50% chance to save, it's an average of 21 damage per target. Compare that with our attacks: with a 60% chance to hit, we're talking 1d6+5 (possibly still only +4 at this level depending on which feats we grab) or 8.5x.6, or 5.1 twice (10.2) plus 3.5x84% (2.94) and then we'll say 3.5/20x3, or .525, giving us a total average of 13.665 damage. So, yeah, the Lightning Bolt is definitely out-damaging that even in single-target situations, but it's a precious 3rd level spell slot.

Haste is adding an extra attack each turn (naturally, we might cast it on someone who hits harder in our party, but we're doing this in a vacuum). That means that we've got another chance for our bonus d6 if we miss twice with our normal action (making it a 93.6% chance to happen) and then an additional 13.14 damage - which does out-do our Dragon's Breath from the Homunuclus (in single-target) and also frees up the Homunculus to use its own attack, which only does a little damage, but hey, it's something.

Now, we haven't talked about Magic Weapon and Elemental Weapon. The rules are slightly ambiguous as to whether you can separately replicate your built-in weapons to get +1 versions of them. Also, if the armor is magical (if you've got, say, +1 Plate) does that mean the weapons are magical as well, and thus not suitable for these spells?

But let's take a look at how, Elemental Weapon would affect our damage:

At 3rd level, we're getting a +1 bonus to attack and damage rolls and an extra d4 damage on a hit.

Thus, in our standard scenario, we now have a 65% chance to hit, and our hits land for 1d6+1d4+5 (we'll assume we're just taking General feats and won't cap Int until 12). So, our average damage is 11 on a hit. We have a 65% chance to hit, so 11x65% is 7.15, and then 14.3 over two attacks. Now, we have an 87.75% chance to land our bonus d6, so that's 3.5x87.75%, or 3.07 (roughly) per turn. So we get basically 17.37 damage per round. But the part of that coming from the spell, compared to just attacking without it, 13.67 (ish) as we determined earlier, means that this spell is only increasing our damage per turn by about 3.7. By contrast, a 3rd level Dragon's Breath with a 50% chance to fail on saves is 10.5 damage per turn.

So I don't think these weapon-enhancing spells are worth it (the one time I found it clutch was when we were in Curse of Strahd and I cast Magic Weapon on our Gunslinger's non-magic guns, which were doing nothing against the Amber Golems in the Amber Temple).

Ok, now, while I'm focusing mostly on tier 2, if we get up to level 13 and can cast 4th level spells, we should talk about Summon Construct. This will get two attacks that do 1d8+8 (average 12.5) on a hit, so with a 60% hit chance, we're looking at 7.5, and then .225 for crits, doubled to 15.45 damage. How is that? a 4th level Dragon's Breath would let our Homunculus do 5d6 damage on a breath, so with a 50% success rate, we're talking 13.125 - so yeah, this is actually a bit better. While the Construct is vulnerable to getting destroyed, so is the Homunculus, and the Golem's beefier. And hey, the Homunculus is probably shooting lightning bolts with the spell-storing item anyway.

And then, of course for 5th level spells, you can get something like Bigby's Hand, which does decent damage (22.5 average, so with a 60% chance to hit, basically 14.625 including crits, but with some nice utility). But that's not until tier 4, so we won't worry too much about it.

For our Armorer-specific spells that aren't Lightning Bolt, we have a few options - Thunderwave and Fire Shield might help if we're going a melee route. Shatter can be an all right poor-man's Fireball (though it's only a little more damage than Dragon's Breath, and we can get that each round if our Homunculus survives).

    Feats:

Ok, because we have weird, unique weapons, we won't really be able to benefit from any major damage-increasing feats. But what of the more Intelligence-focused ones?

Again, I'm going to leave out the ones from Forge of the Artificer just because they're a bit more setting-specific. So we'll stick to the PHB ones. And I'll stick to those that can increase our Intelligence, as we'll probably be doing that at 4, 8, and 12 (though we can take an ASI if we want to move onto others, like Heavy Armor Master).

Fey Touched is, of course, a classically great one - Misty Step is a fantastic spell. We could pick up Hunter's Mark, though we will probably want to concentrate on a different spell pretty early on (Dragon's Breath, again, as a prime example - this is a spell that wouldn't be so good if we didn't have a little Homunculus to be its recipient).

Ritual Caster, actually, would let us get Find Familiar, and thus have a back-up if someone takes down your Homunculus Servant.

Shadow Touched is probably not as popular as Fey Touched, but you could use it to grab Hex, like Fey can get Hunter's Mark, though it has the same problems.

Spell Sniper unfortunately doesn't prevent disadvantage with attacks from your Lightning Launcher, though it does let you ignore partial cover. Unfortunately, Sharpshooter (which could be a good alternative) doesn't boost Intelligence. A decent choice after we've capped our Int (though a pretty big commitment to the Infiltrator mode).

Telekinetic is a pretty great one, actually - especially given that we don't really need our bonus action for much, and the shoving can combine with the Force Demolisher to give us a bit more battlefield control.

Telepathic is also solid, though it's a little less combat-focused.

War Caster, of course, is always a great choice, and especially if we're in melee more. We'll want to make sure we've got some single-target spells. I think that as long as you only choose the creature provoking the opportunity attack, you should be able to use Magic Missile.

    Replicated Magic Items:

Ah yes, a core element of the Artificer.

First, let's talk weapons. My interpretation of the rules is that you can replicate the weapons built into your armor, and that they're separate from the armor itself, so you could have a +1 Lightning Launcher and +1 Plate. If that's the case, these will be high priorities:

+1 Weapons are going to be the obvious choice once you get your subclass. We don't need a Repeating Shot given that the Lightning Launcher doesn't have ammo. Now: there's another matter of interpretation: does having "Weapon, +1" give you the ability to replicate any +1 weapon when you finish a long rest, or just one you choose the plans for? And if you swap your armor model, does that mean you can't make the right weapon for it? D&D Beyond is no help here because it doesn't even list a "Dazzling Force Demolisher" as an option. If I were the DM, I'd grandfather the old version of the Armorer that lets the Infusion transfer between weapons when you swap your armor model, and thus let you at the very least learn "+1 Armorer weapon," though I'd probably just say you have plans for "any +1 weapon."

At level 6, we get some new options. Unless we're struggling with how many plans we're swapping out (we'll want to get +1 Plate at this level, swapping from, like, Gleaming Plate) we can easily grab Dazzling Weapon and replace the +1 version, as you get the +1 bonus with that anyway along with other stuff. Weapon of Warning will sacrifice the +1 bonus, but you do get advantage on initiative, which is nice.

At 10, we probably want to upgrade to a +2 weapon - it's not actually that big of a jump in power, and so we might stick with one of the others we got at level 6 potentially.

At 14, though, we hit a point where we actually need to seriously reconsider our Armor Model, because we can get a Flame Tongue Force Demolisher. Flame Tongues can only be melee weapons, so this will work for that or the Thunder Pulse weapon, but not the Lightning Launcher. A Flame Tongue grants no bonus to attacks, but it does add 2d6 fire damage on a hit (you need to activate it with a bonus action). That extra damage is enormous, and will wipe out any damage you'd be losing from the lower chance to hit. Basically, by level 15, if we have this, the Force Demolisher is going to be landing for 4d6+5 damage on a hit, which is serious damage.

Now, what about other stuff?

Items with charges can be really great thanks to Magic Item Tinker, which lets us charge them up with spell slots, or more likely, to drain them for spell slots. Indeed, if you have two plans for items with charges, just use the first one up, transmute it into the other, and then drain it for peak efficiency.

Some good options here are Wand of Web, Pipes of Haunting, Mind Sharpener. Necklace of Fireballs doesn't technically have "charges," but given that you can just use it up and then transmute it into something else is pretty great.

So, let's imagine a scenario and see how much damage we're going to be putting out.

Let's imagine a big boss fight at level 10 - the conclusion of some major arc. I think a Death Knight functions pretty well (if it's on its own, otherwise it's too difficult) as a tier 2 big bad.

So, at this level we don't have the final slew of replicated magic items, but we can get a +2 weapon. We also don't have Replicate Magic Item yet (we're very close). If we're grabbing all the General Feats we can, we're talking still a +4 to Int.

Our Death Knight has an AC of 20 and a Dex save bonus of +6. 

If we have +4 to Int, we're looking at a spell save DC of 16, and we're rocking a +2 Lightning Launcher and thus have a +10 to hit. We have a Homunculus Servant.

If we're not worrying about battlefield control and just trying to zap as much damage as we can, here's a gameplan:

We cast Dragon's Breath with a bonus action, upcasting to 3rd level, on our Homunculus. Then, we make two attacks with our Lightning Launcher.

Each attack has a 55% chance to hit. They deal 1d6+6 damage, or 9.5 damage on average, on a hit, and add 3.5 on a crit. So, 55%x9.5 (which is 5.225) plus 5%x3.5 (.175) gives us 5.4 per attack, or 10.8.

We then have our bonus d6, with a 79.75% chance to land on our turn. That gives us 3.5x79.75%, or 2.79125.

Now, to get really crunchy, the crit chance on that bonus d6 is 5% on the first attack, but then, the chance of it critting on the second attack is only 5% x 45% (as we'd only get to crit with it if we hadn't hit on the second attack) so we're talking 5%x145%, which comes to 7.25%, which we then apply to our 3.5 from the d6, giving us .25375 damage.

Thus, from our Lightning Launcher, we're doing a total of 13.845 damage per turn. Not... amazing, but continuing on:

We can cast Dragon's Breath on our Homunculus Servant at 3rd level, which means it will be doing 4d6 damage on a failed save, or 14 average, and then 7 average on a successful save. This should happen every turn, so we can easily just add it to the damage turn-by-turn. The Death Knight has a 55% chance to succeed, so 55% of the time we're doing 7 damage and 45% of the time, we're doing 14. 14x45% is 6.3 and 7x55% is 3.85, so the spell nets us an average of 10.15.

Thus, that brings our total damage per turn to 23.995, which is better, but not amazing.

However, if this is a serious boss fight, it stands to reason that we're going whole hog. At level 10, we only have 2 3rd level spell slots. Should we just blow them on Lightning Bolt?

Lighting Bolt does 8d6, or 28 average damage on a failure. But our DK foe has a pretty good saving throw bonus, so again, 55% of the time they're only taking 14. 14x55% is 7.7 and 28x45% is 12.6, so on average our Lightning Bolt is doing 20.3 damage.

Now, we could do this twice, but this would mean downgrading our Dragon's Breath to a 2nd level (and we'd only be able to start casting Lightining Bolt on turn 2, as we still need to cast Dragon's Breath on the first turn). I believe we can just take our average 3rd level Dragon's Breath damage and cut it to 75% (because it's 3d6 instead of 4d6) so that should give us 7.6125 damage per turn.

Thus, if we do it this way, we can do 21.4575 damage on turn 1, and then on turns 2 and 3, we can do 27.9125 damage. I'd say we're now talking at least respectable, if not insane damage.

Notably, one level later, things change profoundly: we'll be having our Homunculus flying off at a safe distance and shooting a Lightining Bolt probably every round of combat with the Spell-Storing Item, which does take Dragon's Breath out of the equation, but that's doubling what Dragon's Breath was doing, and we can just start things off with our own Lightning Bolts as well, so that's basically 40.6 damage on turns 1 and 2 and then dropping to 34.145 after that, which I honestly think is quite solid.