Staff-And-Board Eldritch Knight Build

 So, there are a couple things that I hadn't really considered until recently.

First off: as an Eldritch Knight, you have an odd conundrum. You can use an Arcane Focus for your spells, which is great, but you don't get to use your weapons as arcane foci. It seems like an insane oversight that in 2024, the updated EK didn't change War Bond to let you use the bonded weapon as a spell focus. The feature is almost never relevant.

Why do we need an arcane focus? Well, if you have any kind of set-up where you've got both hands occupied, you technically can't perform the somatic components of spells. As such, my old Dragonborn EK Jax would constantly have to drop his +1 Battleaxe when he wanted to cast Shield, and then pick it up on his next turn.

There is some ambiguity over whether you can still use somatic components in a hand that is holding a spell focus when the spell itself doesn't have a material component, but I think the reasonable common-sense reading is that you could.

And so, we come to the Staff - an Arcane Focus option. It costs more than a Quarterstaff (5 gold rather than 2 silver) but it also pretty explicitly states that the Staff can also be used as a Quarterstaff.

And that solves Jax's problem.

Despite their size, Quarterstaffs (quarterstaves?) are one-handed weapons. You can bump them up to a d8 damage die if you wield them with two hands, but you don't have to.

The second thing I realized is that, 99% of the time when I think about the Polearm Master feat, I imagine using it with a Heavy Reach weapon - the Halberd, Glaive, Lance, or Pike. But it actually works fine with both Spears and Quarterstaffs - both its Pole Strike and Reactive Strike features can work with those weapons as well. (Screw Tridents, I guess).

So, I thought I'd try a build that uses this to allow the Fighter to focus on feats that boost Strength and doesn't need to worry about picking up War Caster. Notably, using a two-handed weapon actually also makes this less of an issue because we have a hand free when we're not in the middle of an attack. But if we truly wanted to never have to worry about material components or somatic components at all, or we wanted to go for a "sword"-and-board build, this does work for us.

And while we won't be hitting as hard with a Quarterstaff as we would with a Glaive (and more importantly miss out on Graze,) the addition of that Pole Strike attack could make this do pretty decent damage. I think.

    Now, I've been doing a lot of calculations for these builds when fighting a Death Knight, which feels like a pretty epic final boss of a campaign that ends at level 10. But I think the Death Knight's super-high armor, damage immunities, and other things might be skewing some of my results a little.

As such, I'm going to calculate this against a more typical enemy. The key takeaway is that we shouldn't compare this damage output with the various builds we've been doing for the last month. This is going to be higher than it would be against a Death Knight.

What monster to fight, though? Well, a level 10 character accounts for an XP budget of 1600, 2300, or 3100 xp in a low, medium, or high difficulty encounter, respectively. That'd be a CR 6 monster at medium difficulty. Chimeras, Wyverns, and Medusas all fit in that CR range, though I think probably the former and latter are more likely to be encountered on their own, so we'll use Wyverns, which feel like pretty standard fantasy monsters that can fit in tons of campaigns.

So, that's what we'll use for our standard monster example (they all have similar ACs, which is encouraging).

Now, the build!

    Weapons:

I think I laid this out pretty clearly - we're using a Staff in our main hand and a shield in our off hand. This will deal 1d6 damage and has the topple mastery (which could be amazing if we're fighting the monster mid-air, but we'll assume we're on the ground).

    Spells:

Naturally, as an Eldritch Knight, we're going to want Booming Blade and Green-Flame Blade. If the Wyvern has a rider, GFB is a great option here, but we're going to focus on the primary target.

Once again, I think the only really clear spell to boost our damage at this level (I did say we were level 10, right?) is going to be Enlarge/Reduce, making us big to add a d4 to each attack. We can burn our Action Surge to cast it and then get our normal attacks.

Beyond that, I'd probably save spells for Shield and such.

    Feats:

Ok, because we've got our spell focus in hand, we don't need to grab War Caster (the advantage on concentration saves would be great, as would the opp attack spells, but we can afford to delay it).

So, to start off, for our Fighting Style we'll grab Dueling. Yeah, maybe if we're going sword-and-board we'd want to go Defensive for ourselves or Interception for our friends, but I think we can stand to push a little more into damage (and this will help mitigate the low damage of the quarterstaff as well). If we want to leave the option open to go for a two-handed weapon, we could take something like Defensive or Blind Fighting, or again, Interception. but for the purposes of this build, we'll assume Dueling.

Then, we grab Polearm Master at level 4, boosting Strength to 18 and giving us mainly our Pole Strike bonus action (Reactive Strike can be all well and good, but we're not going to factor it into our calculations). This lets us just make a bonus action d4 attack every turn as long as we're attacking, which is nearly as much damage as the quarterstaff normally gets.

For level 6, I'd grab Mage Slayer, which feels like it should be a martial staple from now on, though it doesn't increase our damage.

At level 8, if we want to fully commit to sword-and-board for the rest of our career, we could go Shield Master. Alternatively, if we want a bit more survivability, we could grab Heavy Armor Master. Sentinel might be the better option, and gets better if we want to keep open the option that we might use a two-handed polearm instead (though Dueling doesn't really work with that) but is still great for us as-is. So, I think we'll stick to Sentinel.

    Game Plan:

So, pretty simple: we Enlarge ourselves and then whack them with the staff twice, weaving in Booming Blade or Green-Flame Blade as appropriate.

There is one nuance we need to address, though:

If we knock them prone with the Topple Mastery, we can assume they'll spend half their movement to stand up. But does this count as moving to trigger Booming Blade? Thanks to Tactical Master, we can always swap our mastery to something else if we've already knocked them prone, so we could force that thunder damage if they want to get up and attack us again. There'll be some weird math to take into account, but the main thing is we can assume our first attack doesn't get advantage one way or another because they'll have stood up by the time it comes back to our turn.

As such, we'll save Booming Blade for our second attack.

Ok, so first attack is simple:

We have a +5 to Strength, and thus we have a +9 to hit with our attacks. Against the Wyvern's AC of 14, that means that we're going to be hitting 80% of the time. A hit deals 1d6+1d4+7 damage, or 13 on average, with an extra 6 on a crit. So, that's 10.4 plus .65 for a total of 11.05 average on this first attack.

Now:

If we do hit, the Wyvern needs to make a Con save against our Topple DC. That's going to be 17 at this level. With a +3 to Con saves, the Wyvern has to roll a 14 or higher to avoid falling prone. Thus, that's a 65% chance that they do fall prone. However, that only happens if we hit, which is 80%, meaning the total chance that the target is prone and thus giving us advantage on our next attack is 80%x65%, or 52%.

Now, I believe your Pole Strike has to come after your Attack Action, so we'll say the Booming Blade attack comes next.

If we don't have advantage, we'll have the same 80% chance to hit. This hit will, however, deal 1d6+1d8+1d4+7, or an average of 17.5, and an extra 10.5 on a crit. So, when we don't have advantage, we'll deal 17.5x80% plus 10.5x5%, which gives us 14 plus .525. That's pretty easy to add together. However, this only happens 48% of the time (which is fine because it'll be higher when we add the advantage version) so this contributes 14.525x48%, or 6.972.

If we do have advantage, that 80% chance becomes 96%, and the crit chance becomes 9.75%, so 17.5x96% is 16.8 and 10.5x9.75% is about 1.02375, so we're looking at about 17.82. This, then, is going to be 52% of the time, so it's roughly 9.3 damage.

Thus, our Booming Blade attack does about 16.3 damage on average.

(For future stuff here, we'll need to also figure out the average chance Booming Blade hits, which is 80%x48% plus 96%x52%, which gives us 38.4% plus 49.92%, or a total of 88.32%. We'll just hold onto this).

Now, our bonus action Pole Strike is where this gets more complicated.

If we successfully knocked the Wyvern prone on our first attack, we'd just swap to something like Sap on the Booming Blade attack. But if we hadn't, we'll still try to knock them prone. I actually think this winds up just being the same as if we were figuring out if they fell on either of two attacks - we don't need to consider how getting advantage on the second attack would have affected this because, well, we wouldn't have had it. So I think this becomes the inverse of 48% squared. Thus, we wind up with a roughly 77% chance to have them prone by the time we make our Pole Strike.

For the Pole Strike, we're going to use Tactical Master now to swap to Push, in an effort to trigger Booming Blade's extra damage.

Once again, we're looking at 80%/5% and 96%/9.75% for hits/crits, just in different ultimate proportions.

Our hits are less, though, here. On a hit, we deal 2d4+7, or 12 average, and 5 extra on a crit.

Without advantage, that's 12x80%, or 9.6, plus .25 for crits, so 9.85 overall. However, we only don't have advantage 23% of the time, so this contributes roughly 2.27.

With advantage, it's 12x96%, or 11.52, plus 5x9.75%, which is .4875, so we get almost exactly 12. And this happens 77% of the time, so it contributes 9.24.

Thus, the Pole Strike gives us an average of 11.51 damage.

Ok! So! On our turn, we should thus do 38.86 damage (this looks incredible compared to the Death Knight builds, but remember that this is a way lower AC monster).

However, there are two other things to consider:

Reaction strikes and Booming Blade bonus damage.

A few things have to happen for Booming Blade's extra damage to go off. We'll assume that if we do push the Wyvern that we're going to push them out of reach of us and any of our allies, and that they will need to move in some way. I think it's reasonable to say that "standing up" doesn't trigger Booming Blade's extra damage, so we're really just seeing if we A: hit with Booming Blade and B: successfully push the Wyvern away.

We figured out the chance to hit with Booming Blade earlier, which is 88.32%. Great. But we only get that damage if the Wyvern moves (on its own,) so we also need to land the Push attack with our Pole Strike.

23% of the time, we have an 80% chance to have advantage, and 77% of the time, we have a 96% chance to hit. Thankfully, there's no save versus Push. So, 80%x23% is 18.4%, and 96%x77% is 73.92%, so this winds up being a 92.32% chance we've been able to push them.

Oh no.

See, hitting them with the Booming Blade is also part of the math on determining if we topple them.

Uh, screw it, I'm going to keep going. I don't know how much that would change the math here, but it's probably not huge.

Actually, wait, no, it's fine, because we're going to try to push them anyway to get a reactive strike, so we'll be doing this whether or not the Booming Blade hit.

So, basically, we get the 2d8 (9 average) thunder damage from Booming Blade's secondary damage if we hit first with Booming Blade and then again with Pole Strike, so it's 88.32% times 92.32%, or about 81.54%. So, we add 9x81.54% to our total damage per round, giving us about 7.34 more damage.

That brings us up to 46.2 damage per round.

Lastly, we have our reaction strike.

Now, thanks to Sentinel and Polearm Master, there are a lot of ways for us to get a reaction attack. It is a bit dependent on enemy behavior. The worst case is if we fail to push them and they just attack us, which means no attack. But if they go after a nearby ally (we'll be out of range if we did push them, though) or if they do come back toward us after we push them, we can nail them with an attack.

There are too many factors at play here to get a strict probability, but for our "white room" scenario here, we'll assume that if our Push landed, we'll get to make this attack. We'll also assume they're not crawling toward us, so we won't have advantage.

Thus, it's our normal 80%/5% chance. In fact, I think all the math is the same as our first attack, so we can just add 11.05 damage - but only if we did get to Push them, which, as we determined earlier, is a 92.32%. Thus, this adds about 10.2 damage per round.

And that gives us an average of 56.4 damage per round.

Once again, I need to emphasize that we can't compare this to the earlier builds because the hit chance is so much higher than all our "vs Death Knight" ones.

Still, I'm inclined to think that this is pretty good.